Electronic brake system and operation method therefor

ABSTRACT

The present disclosure relates to an electronic brake system. The electronic brake system includes a reservoir in which a pressurized medium is stored, an integrated master cylinder having a master chamber and a simulation chamber, a reservoir flow path provided to communicate the integrated master cylinder with the reservoir, a hydraulic pressure supply device provided to generate a hydraulic pressure by operating a hydraulic piston according to an electrical signal output in response to a displacement of the brake pedal, a hydraulic control unit including a first hydraulic circuit provided to control the hydraulic pressure to be transferred to two wheel cylinders, and a second hydraulic circuit provided to control the hydraulic pressure to be transferred to the other two wheel cylinders, and an electronic control unit configured to control valves based on hydraulic pressure information and displacement information of the brake pedal.

TECHNICAL FIELD

The present disclosure relates to an electronic brake system and anoperation method thereof, and more particularly, to an electronic brakesystem and an operation method thereof for generating a braking forceusing an electrical signal corresponding to a displacement of a brakepedal.

BACKGROUND ART

In general, vehicles are essentially equipped with a brake system forperforming braking, and various types of brake systems have beenproposed for the safety of drivers and passengers.

In a conventional brake system, a method of supplying a hydraulicpressure required for braking to wheel cylinders using a mechanicallyconnected booster when a driver depresses a brake pedal has been mainlyused. However, as market demands to implement various braking functionsin a detailed response to operation environments of vehicles increase,in recent years, an electronic brake system, that receives an electricalsignal corresponding to a pressing force by a driver from a pedaldisplacement sensor that detects a displacement of a brake pedal whenthe driver depresses the brake pedal and operates a hydraulic pressuresupply device based on the electric signal to supply a hydraulicpressure required for braking to wheel cylinders, have been widely used.

In such an electronic brake system, an electrical signal is generatedand provided when a driver depresses the brake pedal in a normaloperation mode, and based on the electric signal, the hydraulic pressuresupply device is electrically operated and controlled to generate ahydraulic pressure required for braking and transfer the hydraulicpressure to the wheel cylinders. As such, although such an electronicbrake system and an operation method are electrically operated andcontrolled so that complex and various braking operations may beimplemented, when a technical problem occurs in an electric component, ahydraulic pressure required for braking may not be stably generated, andthus the safety of passengers may not be secured.

Therefore, the electronic brake system enters the abnormal operationmode when a component fails or becomes out of control, and in this case,a mechanism is required in which the operation of the brake pedal by adriver is directly linked to the wheel cylinders. That is, in theabnormal operation mode in the electronic brake system, as the driverdepresses the brake pedal, a hydraulic pressure required for brakingneeds to be generated immediately and transferred directly to the wheelcylinders.

DISCLOSURE Technical Problem

The present disclosure is directed to providing an electronic brakesystem capable of reducing the number of parts to be applied andachieving a miniaturization and lightweight of a product.

The present disclosure is directed to providing an electronic brakesystem capable of effectively implementing braking in various operatingsituations.

The present disclosure is directed to providing an electronic brakesystem capable of stably generating a high-pressure braking pressure.

The present disclosure is directed to providing an electronic brakesystem capable of improving performance and operational reliability.

The present disclosure is directed to providing an electronic brakesystem capable of improving durability of a product by reducing loadsapplied to components.

The present disclosure is directed to providing an electronic brakesystem capable of improving easiness of assembly and productivity of aproduct and reducing a manufacturing cost of the product.

Technical Solution

An aspect of the present disclosure provides an electronic brake systemincluding a reservoir in which a pressurized medium is stored, anintegrated master cylinder having a master chamber and a simulationchamber and connected to a brake pedal to discharge the pressurizedmedium, a hydraulic pressure supply device provided to generate ahydraulic pressure by operating a hydraulic piston according to anelectrical signal output in response to a displacement of the brakepedal, a hydraulic control unit including a first hydraulic circuitprovided to control the hydraulic pressure to be transferred to twowheel cylinders, and a second hydraulic circuit provided to control thehydraulic pressure to be transferred to the other two wheel cylinders,and an electronic control unit configured to control valves based onhydraulic pressure information and displacement information of the brakepedal, wherein the hydraulic pressure supply device includes a firstpressure chamber provided on one side of the hydraulic piston movablyaccommodated in a cylinder block to be connected to one or more of thewheel cylinders, and a second pressure chamber provided on the otherside of the hydraulic piston to be connected to one or more of the wheelcylinders, and wherein the hydraulic control unit includes a firsthydraulic flow path in communication with the first pressure chamber, asecond hydraulic flow path branched from the first hydraulic flow pathto be connected to the first hydraulic circuit, a third hydraulic flowpath branched from the first hydraulic flow path to be connected to thesecond hydraulic circuit, a fourth hydraulic flow path in communicationwith the second pressure chamber, a fifth hydraulic flow path branchedfrom the fourth hydraulic flow path to be connected to the firsthydraulic circuit, a sixth hydraulic flow path branched from the fourthhydraulic flow path to be connected to the second hydraulic circuit, aseventh hydraulic flow path branched from the first hydraulic flow path,an eighth hydraulic flow path branched from the fourth hydraulic flowpath, a ninth hydraulic flow path in which the seventh hydraulic flowpath and the eighth hydraulic flow path join, a tenth hydraulic flowpath branched from the ninth hydraulic flow path to be connected to thefirst hydraulic circuit, and an eleventh hydraulic flow path branchedfrom the ninth hydraulic flow path to be connected to the secondhydraulic circuit.

The hydraulic control unit may include a first valve provided in thesecond hydraulic flow path to control a flow of the pressurized medium,a second valve provided in the third hydraulic flow path to control theflow of the pressurized medium, a third valve provided in the fifthhydraulic flow path to control the flow of the pressurized medium, afourth valve provided in the sixth hydraulic flow path to control theflow of the pressurized medium, a fifth valve provided in the seventhhydraulic flow path to control the flow of the pressurized medium, asixth valve provided in the eighth hydraulic flow path to control theflow of the pressurized medium, a seventh valve provided in the tenthhydraulic flow path to control the flow of the pressurized medium, andan eighth valve provided in the eleventh hydraulic flow path to controlthe flow of the pressurized medium.

The first valve may be provided as a check valve for allowing only theflow of the pressurized medium from the first hydraulic flow path towardthe first hydraulic circuit, the second valve may be provided as a checkvalve for allowing only the flow of the pressurized medium from thefirst hydraulic flow path toward the second hydraulic circuit, the thirdvalve may be provided as a check valve for allowing only the flow of thepressurized medium from the fourth hydraulic flow path toward the firsthydraulic circuit, the fourth valve may be provided as a check valve forallowing only the flow of the pressurized medium from the fourthhydraulic flow path toward the second hydraulic circuit, the fifth valveand the sixth valve may be provided as solenoid valves for controllingbidirectional flows of the pressurized medium, the seventh valve may beprovided as a check valve for allowing only the flow of the pressurizedmedium from the first hydraulic circuit toward the ninth hydraulic flowpath, and the eighth valve may be provided as a check valve for allowingonly the flow of the pressurized medium from the second hydrauliccircuit toward the ninth hydraulic flow path.

The electronic brake system may further include a dump controllerprovided between the reservoir and the hydraulic pressure supply deviceto control the flow of the pressurized medium, wherein the dumpcontroller may include a first dump flow path provided to connect thefirst pressure chamber and the reservoir, a first dump check valveprovided in the first dump flow path to allow only the flow of thepressurized medium from the reservoir toward the first pressure chamber,a first bypass flow path connected in parallel with respect to the firstdump check valve on the first dump flow path, and a first dump valveprovided in the first bypass flow path to control bidirectional flows ofthe pressurized medium.

The dump controller may further include a second dump flow path providedto connect the second pressure chamber and the reservoir, a second dumpcheck valve provided in the second dump flow path to allow only the flowof the pressurized medium from the reservoir toward the second pressurechamber, a second bypass flow path connected in parallel with respect tothe second dump check valve on the second dump flow path, and a seconddump valve provided in the second bypass flow path to controlbidirectional flows of the pressurized medium.

The integrated master cylinder may include a master piston provided inthe master chamber to be displaceable by a brake pedal, a firstsimulation chamber, a first simulation piston provided in the firstsimulation chamber to be displaceable by a displacement of the masterpiston or a hydraulic pressure of the pressurized medium accommodated inthe master chamber, a second simulation chamber, a first simulationpiston provided in the second simulation chamber to be displaceable by adisplacement of the first simulation piston or a hydraulic pressure inthe first simulation piston, and an elastic member provided between thefirst simulation piston and the second simulation piston.

The integrated master cylinder may further include a simulation flowpath provided to connect the first simulation chamber and the reservoir,and a simulator valve provided in the simulation flow path to controlthe flow of the pressurized medium.

The electronic brake system may further include a first backup flow pathprovided to connect the master chamber and the first hydraulic circuit,a second backup flow path provided to connect the first simulationchamber and the second hydraulic circuit, a first cut valve provided inthe first backup flow path to control the flow of the pressurizedmedium, at least one second cut valve provided in the second backup flowpath to control the flow of the pressurized medium, an auxiliary backupflow path provided to connect the second simulation chamber and thesecond backup flow path, and an inspection valve provided in theauxiliary backup flow path to control the flow of the pressurizedmedium.

The first hydraulic circuit may include a first inlet valve and a secondinlet valve provided to control the flow of the pressurized medium to besupplied to a first wheel cylinder and a second wheel cylinder,respectively, and a first outlet valve and a second outlet valveprovided to control the flow of the pressurized medium to be dischargedfrom the first wheel cylinder and the second wheel cylinder to thereservoir, respectively, the second hydraulic circuit may include athird inlet valve and a fourth inlet valve provided to control the flowof the pressurized medium to be supplied to a third wheel cylinder and afourth wheel cylinder, respectively, and the second backup flow path maybe provided to connect at least one of downstream sides of the third andfourth inlet valves and the first simulation chamber.

The electronic brake system may further include a reservoir flow pathprovided to communicate the integrated master cylinder with thereservoir, wherein the reservoir flow path may include a first reservoirflow path provided to connect the reservoir and the master chamber, asecond reservoir flow path provided to connect the reservoir and thefirst simulation chamber, and a third reservoir flow path provided toconnect the reservoir and the second simulation chamber.

The electronic brake system may further include a reservoir valveprovided in the second reservoir flow path to allow only the flow of thepressurized medium from the reservoir toward the first simulationchamber.

The integrated master cylinder may further include a piston springprovided to elastically support the master piston, a first simulatorspring provided to elastically support the first simulation piston, anda second simulator spring provided to elastically support the secondsimulation piston.

Another aspect of the present disclosure provides an operation method ofthe electronic brake system according to claim 4, including a normaloperation mode, wherein the normal operation mode includes a firstbraking mode in which the hydraulic pressure is primarily provided by aforward movement of the hydraulic piston as the hydraulic pressure ofthe pressurizing medium to be transferred from the hydraulic pressuresupply device to the wheel cylinders gradually increases, and a secondbraking mode in which the hydraulic pressure is secondarily provided bya backward movement of the hydraulic piston after the first brakingmode.

In the first braking mode, the fifth valve and the sixth valve may beopened and the first dump valve may be closed, and the hydraulicpressure generated in the first pressure chamber by the forward movementof the hydraulic piston may be provided to the first hydraulic circuitby sequentially passing through the first hydraulic flow path and thesecond hydraulic flow path, and provided to the second hydraulic circuitby sequentially passing through the first hydraulic flow path and thethird hydraulic flow path, and wherein at least a part of the hydraulicpressure generated in the first pressure chamber may be supplied to thesecond pressure chamber by sequentially passing through the firsthydraulic flow path, the seventh hydraulic flow path, the eighthhydraulic flow path, and the fourth hydraulic flow path.

In the second braking mode, the fifth valve may be closed, and thehydraulic pressure generated in the first pressure chamber by a backwardmovement of the hydraulic piston after the first braking mode may beprovided to the first hydraulic circuit by sequentially passing throughthe fourth hydraulic flow path and the fifth hydraulic flow path, andprovided to the second hydraulic circuit by sequentially passing throughthe fourth hydraulic flow path and the sixth hydraulic flow path.

Another aspect of the present disclosure provides an operation method ofthe electronic brake system according to claim 5, including a normaloperation mode, wherein the normal operation mode includes a firstbraking mode in which the hydraulic pressure is primarily provided by aforward movement of the hydraulic piston as the hydraulic pressure ofthe pressurizing medium to be transferred from the hydraulic pressuresupply device to the wheel cylinders gradually increases, a secondbraking mode in which the hydraulic pressure is secondarily provided bya backward movement of the hydraulic piston after the first brakingmode, and a third braking mode in which the hydraulic pressure isthirdly provided by the forward movement of the hydraulic piston afterthe second braking mode.

In the first braking mode, the sixth valve and the first dump valve maybe closed, and the hydraulic pressure generated in the first pressurechamber by the forward movement of the hydraulic piston may be providedto the first hydraulic circuit by sequentially passing through the firsthydraulic flow path and the second hydraulic flow path, and provided tothe second hydraulic circuit by sequentially passing through the firsthydraulic flow path and the third hydraulic flow path.

In the second braking mode, the fifth valve and the second dump valvemay be closed, and the hydraulic pressure generated in the firstpressure chamber by a backward movement of the hydraulic piston afterthe first braking mode may be provided to the first hydraulic circuit bysequentially passing through the fourth hydraulic flow path and thefifth hydraulic flow path, and provided to the second hydraulic circuitby sequentially passing through the fourth hydraulic flow path and thesixth hydraulic flow path.

In the third braking mode, the fifth valve and the sixth valve may beopened and the first dump valve and the second dump valve may be closed,and a part of the hydraulic pressure generated in the first hydrauliccircuit by the forward movement of the hydraulic piston may be providedto the first hydraulic circuit by sequentially passing through the firsthydraulic flow path and the second hydraulic flow path, and provided tothe second hydraulic circuit by sequentially passing through the firsthydraulic flow path and the third hydraulic flow path, and wherein theremaining part of the hydraulic pressure generated in the first pressurechamber may be supplied to the second pressure chamber by sequentiallypassing through the first hydraulic flow path, the seventh hydraulicflow path, the eighth hydraulic flow path, and the fourth hydraulic flowpath.

Advantageous Effects

An electronic brake system according to the present embodiment canreduce the number of parts to be applied and achieve a miniaturizationand lightweight of a product.

The electronic brake system according to the present embodiment canstably and effectively implement braking in various operating situationsof a vehicle.

The electronic brake system according to the present embodiment canstably generate a high-pressure braking pressure.

The electronic brake system according to the present embodiment canimprove performance and operational reliability of the product.

The electronic brake system according to the present embodiment canstably provide a braking pressure even when a component fails or apressurized medium leaks.

The electronic brake system according to the present embodiment canimprove durability of the product by reducing loads applied tocomponents.

The electronic brake system according to the present embodiment canimprove easiness of assembly and productivity of the product and reducea manufacturing cost of the product.

DESCRIPTION OF DRAWINGS

FIG. 1 is a hydraulic circuit diagram illustrating an electronic brakesystem according to a first embodiment of the present disclosure.

FIG. 2 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosureperforms a first braking mode.

FIG. 3 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosureperforms a second braking mode.

FIG. 4 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosurereleases the second braking mode.

FIG. 5 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosurereleases the first braking mode.

FIG. 6 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosureperforms an abnormal operation mode (fallback mode).

FIG. 7 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the first embodiment of the present disclosureperforms an inspection mode.

FIG. 8 is a hydraulic circuit diagram illustrating an electronic brakesystem according to a second embodiment of the present disclosure.

FIG. 9 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure performs a first braking mode.

FIG. 10 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure performs a second braking mode.

FIG. 11 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure performs a third braking mode.

FIG. 12 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure releases the third braking mode.

FIG. 13 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure releases the second braking mode.

FIG. 14 is a hydraulic circuit diagram illustrating that the electronicbrake system according to the second embodiment of the presentdisclosure releases the first braking mode.

MODE OF THE DISCLOSURE

Hereinafter, an embodiment of the present disclosure will be describedin detail with reference to the accompanying drawings. The followingembodiment is provided to fully convey the spirit of the presentdisclosure to a person having ordinary skill in the art to which thepresent disclosure belongs. The present disclosure is not limited to theembodiment shown herein but may be embodied in other forms. The drawingsare not intended to limit the scope of the present disclosure in anyway, and the size of components may be exaggerated for clarity ofillustration.

FIG. 1 is a hydraulic circuit diagram illustrating an electronic brakesystem 1000 according to a first embodiment of the present disclosure.

Referring to FIG. 1, the electronic brake system 1000 according to thefirst embodiment of the present disclosure includes a reservoir 1100 inwhich a pressurized medium is stored, an integrated master cylinder 1200provided to provide a reaction force against pressing of a brake pedal10 to a driver and pressurize and discharge the pressurized medium suchas brake oil accommodated therein, a hydraulic pressure supply device1300 provided to receive an electrical signal corresponding to apressing force by a driver from a pedal displacement sensor 11 thatdetects a displacement of the brake pedal 10 and to generate a hydraulicpressure of the pressurized medium through a mechanical operation, ahydraulic control unit 1400 provided to control the hydraulic pressureprovided from the hydraulic pressure supply device 1300, hydrauliccircuits 1510 and 1520 having wheel cylinders 20 for braking respectivewheels RR, RL, FR, and FL as the hydraulic pressure of the pressurizedmedium is transferred, a dump controller 1800 provided between thehydraulic pressure supply device 1300 and the reservoir 1100 to controla flow of the pressurized medium, backup flow paths 1610 and 1620 areprovided to hydraulically connect the integrated master cylinder 1200and the hydraulic circuits 1510 and 1520, a reservoir flow path 1700provided to hydraulically connect the reservoir 1100 and the integratedmaster cylinder 1200, and an electronic control unit (ECU, not shown)provided to control the hydraulic pressure supply device 1300 andvarious valves based on hydraulic pressure information and pedaldisplacement information.

The integrated master cylinder 1200 includes simulation chambers 1230 aand 1240 a, and a master chamber 1220 a to, when the driver presses thebrake pedal 10 for braking operation, provide a reaction force againstthe pressing to the driver to provide a stable pedal feel, and at thesame time pressurize and discharge the pressurized medium accommodatedtherein.

The integrated master cylinder 1200 may be divided into a pedalsimulation part to provide a pedal feel to the driver, and a mastercylinder part to transfer the pressurized medium to the first hydrauliccircuit 1510 side, which will be described later. The integrated mastercylinder 1200 may be configured such that the master cylinder part andthe pedal simulation part are sequentially provided from the brake pedal10 side and disposed coaxially within a cylinder block 1210.

Specifically, the integrated master cylinder 1200 may include thecylinder block 1210 having a chamber formed therein, the master chamber1220 a formed on an inlet side of the cylinder block 1210 to which thebrake pedal 10 is connected, a master piston 1220 provided in the masterchamber 1220 a and connected to the brake pedal 10 to be displaceabledepending on the operation of the brake pedal 10, a piston spring 1220 bprovided to elastically support the master piston 1220, the firstsimulation chamber 1230 a formed more inside than the master chamber1220 a on the cylinder block 1210, a first simulation piston 1230provided in the first simulation chamber 1230 a to be displaceable by adisplacement of the master piston 1220 or a hydraulic pressure of thepressurized medium accommodated in the master chamber 1220 a, the secondsimulation chamber 1240 a formed more inside than the first simulationchamber 1230 a on the cylinder block 1210, a second simulation piston1240 provided in the second simulation chamber 1240 a to be displaceableby a displacement of the first simulation chamber 1230 a or a hydraulicpressure of the pressurized medium accommodated in the first simulationchamber 1230 a, an elastic member 1250 disposed between the firstsimulation piston 1230 and the second simulation piston 1240 to providea pedal feeling through an elastic restoring force generated duringcompression, a first simulator spring 1271 provided to elasticallysupport the first simulation piston 1230, a second simulator spring 1272provided to elastically support the second simulation piston 1240, asimulation flow path 1260 provided to connect the first simulationchamber 1230 a and the reservoir 1100, and a simulator valve 1261provided in the simulation flow path 1260 to control the flow of thepressurized medium.

The master chamber 1220 a, the first simulation chamber 1230 a, and thesecond simulation chamber 1240 a may be sequentially formed toward theinside (left side of FIG. 1) from the brake pedal 10 side (right side ofFIG. 1) on the cylinder block 1210 of the integrated master cylinder1200. Also, the master piston 1220, the first simulation piston 1230,and the second simulation piston 1240 are disposed in the master chamber1220 a, the first simulation chamber 1230 a, and the second simulationchamber 1240 a, respectively, to generate a hydraulic pressure or anegative pressure by the pressurized medium accommodated in therespective chambers depending on forward or backward movement.

The master chamber 1220 a may be formed on the inlet side or theoutermost side (right side of FIG. 1) of the cylinder block 1210, andthe master piston 1220 connected to the brake pedal 10 via an input rod12 may be accommodated in the master chamber 1220 a to enablereciprocating movement.

The pressurized medium may be introduced into and discharged from themaster chamber 1220 a through a first hydraulic port 1280 a and a secondhydraulic port 1280 b. The first hydraulic port 1280 a is connected to afirst reservoir flow path 1710, which will be described later, so thatthe pressurized medium may be introduced into the master chamber 1220 afrom the reservoir 1100, and the second hydraulic port 1280 b isconnected to a first backup flow path 1610, which will be describedlater, so that the pressurized medium may be discharged into the masterchamber 1220 a from the first backup flow path 1610, or conversely, thepressurized medium may be introduced into the master chamber 1220 a fromthe first backup flow path 1610. A pair of sealing members 1290 a areprovided in front and rear of the first hydraulic port 1280 a to preventleakage of the pressurized medium. The pair of sealing members 1290 amay allow the flow of the pressurized medium from the reservoir 1100toward the first master chamber 1220 a through the first reservoir flowpath 1710, while blocking the flow of the pressurized medium from thefirst master chamber 1220 a toward the first reservoir flow path 1710.

The master piston 1220 may be accommodated in the master chamber 1220 ato generate a hydraulic pressure by pressurizing the pressurized mediumaccommodated in the master chamber 1220 a by moving forward (leftdirection of FIG. 1) or to generate a negative pressure inside themaster chamber 1220 a by moving backward (right direction of FIG. 1).The master piston 1220 may be elastically supported by the piston spring1220 b, and the piston spring 1220 b may be provided with one endsupported by the cylinder block 1210 and the other end supported by aflange portion formed by extending outwardly from an end of the masterpiston 1220.

The first simulation chamber 1230 a may be formed at an inner side (leftside of FIG. 1) of the master chamber 1220 a on the cylinder block 1210,and the first simulation piston 1230 may be accommodated in the firstsimulation chamber 1230 a to enable reciprocating movement.

The pressurized medium may be introduced into and discharged from thefirst simulation chamber 1230 a through a third hydraulic port 1280 cand a fourth hydraulic port 1280 d. The third hydraulic port 1280 c isconnected to a second reservoir flow path 1720 and the simulation flowpath 1260, which will be described later, so that the pressurized mediumaccommodated in the first simulation chamber 1230 a may be dischargedinto the reservoir 1100 side, or conversely, the pressurized medium maybe introduced from the reservoir 1100. The fourth hydraulic port 1280 dis connected to the second backup flow path 1620, which will bedescribed later, so that the pressurized medium accommodated in thefirst simulation chamber 1230 a may be discharged into the secondhydraulic circuit 1520 side, or conversely, the pressurized medium maybe introduced into the first backup flow path 1610 from the firstsimulation chamber 1230 a side.

The first simulation piston 1230 may be accommodated in the firstsimulation chamber 1230 a to generate a hydraulic pressure of thepressurized medium accommodated in the first simulation chamber 1230 aor press the elastic member 1250, which will be described later, bymoving forward, or to generate a negative pressure inside the firstsimulation chamber 1230 a or return the elastic member 1250 to anoriginal position and shape thereof by moving backward. At least onesealing member 1290 b may be provided between an inner wall of thecylinder block 1210 and an outer circumferential surface of the firstsimulation piston 1230 to prevent leakage of the pressurized mediumbetween the adjacent chambers.

A step portion formed to be stepped may be provided at a portion wherethe first simulation chamber 1230 a is formed on the cylinder block1210, and an extension portion provided to be caught on the step portionby expanding outwardly may be provided on the outer circumferentialsurface of the first simulation piston 1230. As the extension portion ofthe first simulation piston 1230 is provided to be caught on the stepportion of the cylinder block 1210, in order for the first simulationpiston 1230 to return to an original position thereof after movingforward by the operation of the brake pedal 10, a backward stroke degreeof the first simulation piston 1230 when moving backward may be limited.

The second simulation chamber 1240 a may be formed at an inner side(left side of FIG. 1) of the first simulation chamber 1230 a on thecylinder block 1210, and the second simulation piston 1240 may beaccommodated in the second simulation chamber 1240 a to enablereciprocating movement.

The pressurized medium may be introduced into and discharged from thesecond simulation chamber 1240 a through a fifth hydraulic port 1280 eand a sixth hydraulic port 1280 f. Specifically, the fifth hydraulicport 1280 e is connected to a third reservoir flow path 1730, which willbe described later, so that the pressurized medium may be introducedinto or discharged from the reservoir 1100 to the second simulationchamber 1240 a side. The sixth hydraulic port 1280 f is connected to anauxiliary backup flow path 1630, which will be described later, so thatthe pressurized medium accommodated in the second simulation chamber1240 a may be discharged into the second backup flow path 1620 side, orconversely, the pressurized medium may be introduced into the secondsimulation chamber 1240 a from the second backup flow path 1620.

The second simulation piston 1240 may be accommodated in the secondsimulation chamber 1240 a to generate a hydraulic pressure of thepressurized medium accommodated in the second simulation chamber 1240 aby moving forward, or to generate a negative pressure inside the secondsimulation chamber 1240 a by moving backward. At least one sealingmember 1290 c may be provided between the inner wall of the cylinderblock 1210 and an outer circumferential surface of the second simulationpiston 1240 to prevent leakage of the pressurized medium between theadjacent chambers. The sealing member 1290 c may allow the flow of thepressurized medium from the reservoir 1100 toward the second simulationchamber 1240 a through the third reservoir flow path 1730, whileblocking the flow of the pressurized medium from the second simulationchamber 1240 a toward the third reservoir flow path 1730.

The integrated master cylinder 1200 according to the present embodimentmay secure safety in the event of a failure of a component by includingthe master chamber 1220 a and the simulation chambers 1230 a and 1240 a.For example, the master chamber 1220 a may be connected to the wheelcylinders 20 of any two of a right front wheel FR, a left front wheelFL, a left rear wheel RL, and a right rear wheel RR through the firstbackup flow path 1610, which will be described later, and the simulationchambers 1230 a and 1240 a may be connected to the wheel cylinders 20 ofthe other two through the second backup flow path 1620 and the auxiliarybackup flow path 1630, which will be described later, and thus even whena problem such as a leak in any one of the chambers occurs, it may bepossible to brake the vehicle. A detailed description thereof will bedescribed later with reference to FIG. 6.

The elastic member 1250 is interposed between the first simulationpiston 1230 and the second simulation piston 1240 and provided toprovide a pedal feeling of the brake pedal 10 to the driver by its ownelastic restoring force. The elastic member 1250 may be made of amaterial such as compressible and expandable rubber, and when adisplacement occurs in the first simulation piston 1230 by the operationof the brake pedal 10, but when the second simulation piston 1240 ismaintained in an original position thereof, the elastic member 1250 iscompressed, and the driver may receive a stable and familiar pedal feelby the elastic restoring force of the compressed elastic member 1250. Adetailed description thereof will be described later.

Accommodating grooves recessed in a shape corresponding to the shape ofthe elastic member 1250 to facilitate smooth compression and deformationof the elastic member 1250 may be provided on a rear surface (leftsurface of FIG. 1) of the first simulation piston 1230 and a frontsurface (right surface of FIG. 1) of the second simulation piston 1240,which face the elastic member 1250, respectively.

The first simulator spring 1271 is provided to elastically support thefirst simulation piston 1230. To this end, one end of the firstsimulation spring 1271 may be supported on the rear surface (leftsurface of FIG. 1) of the first simulation piston 1230, and the otherend may be supported on the front surface (right surface of FIG. 1) ofthe second simulation piston 1240. When the first simulation piston 1230moves forward according to a braking operation and a displacementoccurs, the first simulator spring 1271 is compressed, and at this time,a pedal feeling may be provided to the driver together with the elasticmember 1250 by an elastic restoring force thereof. After that, when thebraking is released, as the first simulator spring 1271 expands by anelastic force thereof, the first simulation piston 1230 may return tothe original position.

The second simulator spring 1272 is provided to elastically support thesecond simulation piston 1240. One end of the second simulation spring1272 may be supported on the cylinder block 1210, and the other end maybe supported on the second simulation piston 1240, thereby elasticallysupporting the second simulation piston 1240. When the second simulationpiston 1240 moves forward according to the braking operation and adisplacement occurs, the second simulator spring 1272 is compressed, andafter that, when the braking is released, as the second simulator spring1272 expands by an elastic force thereof, the second simulation piston1240 may return to the original position.

The simulation flow path 1260 is provided to communicate the firstsimulation chamber 1230 a and the reservoir 1100 with each other, andthe simulator valve 1261 for controlling bidirectional flows of thepressurized medium may be provided in the simulation flow path 1260. Thesimulator valve 1261 may be provided as a normally closed type solenoidvalve that operates to be opened when an electric signal is receivedfrom the electronic control unit in a normally closed state. Thesimulator valve 1261 may be opened in a normal operation mode of theelectronic brake system 1000.

Explaining a pedal simulation operation by the integrated mastercylinder 1200, in a normal operation, at the same time as the driveroperates the brake pedal 10, a first cut valve 1611 and a second cutvalve 1621 provided in the first backup flow path 1610 and the secondbackup flow path 1620, which will be described later, respectively, areclosed, while the simulator valve 1261 in the simulation flow path 1260is open. As the operation of the brake pedal 10 progresses, the masterpiston 1220 moves forward, but the master chamber 1220 a is sealed by aclosing operation of the first cut valve 1611, so that as the hydraulicpressure of the pressurized medium accommodated in the master chamber1220 a is transferred to the first simulation piston 1230, the firstsimulation piston 1230 moves forward to generate a displacement. On theother hand, as the second cut valve 1621 is closed, the secondsimulation chamber 1240 a is sealed so that a displacement of the secondsimulation piston 1240 is not generated, and thus the elastic member1250 and the first simulator spring 1271 are compressed by thedisplacement of the first simulation piston 1230, and the elasticrestoring force by compression of the elastic member 1250 and the firstsimulator spring 1271 may be provided to the driver as a pedal feeling.At this time, the pressurized medium accommodated in the firstsimulation chamber 1230 a is transferred to the reservoir 1100 throughthe simulation flow path 1260. After that, when the driver releases thepressing force of the brake pedal 10, the piston spring 1220 b, theelastic member 1250, and the first simulator spring 1271 return to theoriginal shape and position thereof by the elastic restoring force, andthe first simulation chamber 1230 a may be filled with the pressurizedmedium supplied from the reservoir 1100 through the simulation flow path1260.

As such, because the inside of the first simulation chamber 1230 a andthe second simulation chamber 1240 a is always filled with thepressurized medium, when the pedal simulation is operated, friction ofthe first simulation piston 1230 and the second simulation piston 1240is minimized, so that the durability of the integrated master cylinder1200 is improved, and the inflow of foreign substances from the outsidemay be blocked.

A case in which the electronic brake system 1000 operates abnormally,that is, an operation of the integrated master cylinder 1200 in afallback mode will be described later with reference to FIG. 6.

The reservoir 1100 may accommodate and store the pressurized mediumtherein. The reservoir 1100 may be connected to each component such asthe integrated master cylinder 1200, the hydraulic pressure supplydevice 1300, which will be described later, and the hydraulic circuits,which will be described later, to supply or receive the pressurizedmedium. Although a plurality of the reservoirs 1100 is shown with thesame reference numeral in the drawings, this is only an example forbetter understanding of the present invention, and the reservoir 1100may be provided as a single component, or a plurality of the separateand independent reservoirs 1100 may be provided.

The reservoir flow path 1700 is provided to connect the integratedmaster cylinder 1200 and the reservoir 1100.

The reservoir flow path 1700 may include the first reservoir flow path1710 connecting the master chamber 1220 a and the reservoir 1100, thesecond reservoir flow path 1720 connecting the first simulation chamber1230 a and the reservoir 1100, and the third reservoir flow path 1730connecting the second simulation chamber 1240 a and the reservoir 1100.To this end, one end of the first reservoir flow path 1710 maycommunicate with the master chamber 1220 a of the integrated mastercylinder 1200 and the other end may communicate with the reservoir 1100,one end of the second reservoir flow path 1720 may communicate with thefirst simulation chamber 1230 a of the integrated master cylinder 1200and the other end may communicate with the reservoir 1100, and one endof the third reservoir flow path 1730 may communicate with the secondsimulation chamber 1240 a of the integrated master cylinder 1200 and theother end may communicate with the reservoir 1100. As shown in thedrawing, the second reservoir flow path 1720 may be connected to thereservoir 1100 as the simulation flow path 1260 is branched from thesecond reservoir flow path 1720 and rejoins the second reservoir flowpath 1720, but is not limited thereto, and the second reservoir flowpath 1720 and the simulation flow path 1260 may be connected to thereservoir 1100 independently of each other.

A reservoir valve 1721 for controlling a flow of a braking fluidtransferred through the second reservoir flow path 1720 may be providedin the second reservoir flow path 1720. The reservoir valve 1721 may beprovided as a check valve for allowing the flow of the pressurizedmedium from the reservoir 1100 toward the first simulation chamber 1230a, while blocking the flow of the pressurized medium from the firstsimulation chamber 1230 a toward the reservoir 1100.

The hydraulic pressure supply device 1300 is provided to receive anelectrical signal corresponding to a pressing force of the driver fromthe pedal displacement sensor 11 detecting a displacement of the brakepedal 10 and to generate a hydraulic pressure of the pressurized mediumthrough a mechanical operation.

The hydraulic pressure supply device 1300 may include a hydraulicpressure providing unit to provide a pressure to the pressurized mediumto be transferred to the wheel cylinders 20, a motor (not shown) togenerate a rotational force by an electrical signal from the pedaldisplacement sensor 11, and a power conversion unit (not shown) toconvert a rotational motion of the motor into a linear motion to providethe linear motion to the hydraulic pressure providing unit.

The hydraulic pressure providing unit includes a cylinder block 1310provided such that the pressurized medium may be accommodated, ahydraulic piston 1320 accommodated in the cylinder block 1310, a sealingmember 1350 provided between the hydraulic piston 1320 and the cylinderblock 1310 to seal the pressure chambers 1330 and 1340, and a driveshaft 1390 to transfer power output from the power conversion unit tothe hydraulic piston 1320.

The pressure chambers 1330 and 1340 may include the first pressurechamber 1330 located in the front of the hydraulic piston 1320 (leftdirection of the hydraulic piston 1320 in FIG. 1), and the secondpressure chamber 1340 located in the rear of the hydraulic piston 1320(right direction of the hydraulic piston 1320 in FIG. 1). That is, thefirst pressure chamber 1330 is provided to be partitioned by thecylinder block 1310 and a front surface of the hydraulic piston 1320 sothat a volume thereof varies depending on the movement of the hydraulicpiston 1320, and the second pressure chamber 1340 is provided to bepartitioned by the cylinder block 1310 and a rear surface of thehydraulic piston 1320 so that a volume thereof varies depending on themovement of the hydraulic piston 1320.

The first pressure chamber 1330 is connected to a first hydraulic flowpath 1401, which will be described later, through a first communicationhole 1360 a formed on the cylinder block 1310, and the second pressurechamber 1340 is connected to a fourth hydraulic flow path 1404, whichwill be described later, through a second communication hole 1360 bformed on the cylinder block 1310.

The sealing members include a piston sealing member 1350 a providedbetween the hydraulic piston 1320 and the cylinder block 1310 to sealbetween the first pressure chamber 1330 and the second pressure chamber1340, and a drive shaft sealing member 1350 b provided between the driveshaft 1390 and the cylinder block 1310 to seal between the secondpressure chamber 1340 and an opening of the cylinder block 1310. Thehydraulic pressure or negative pressure of the first pressure chamber1330 and the second pressure chamber 1340 generated by the forward orbackward movement of the hydraulic piston 1320 may not leak by beingsealed by the piston sealing member 1350 a and the drive shaft sealingmember 1350 b and may be transferred to the first hydraulic flow path1401 and the fourth hydraulic flow path 1404, which will be describedlater.

The motor (not shown) is provided to generate a driving force of thehydraulic piston 1320 by an electric signal output from the electroniccontrol unit. The motor may include a stator and a rotor, and throughthis configuration, may provide power to generate a displacement of thehydraulic piston 1320 by rotating in a forward or reverse direction. Arotational angular speed and a rotational angle of the motor may beprecisely controlled by a motor control sensor. Because the motor is awell-known technology, a detailed description thereof will be omitted.

The power conversion unit (not shown) is provided to convert arotational force of the motor into a linear motion. The power conversionunit may be provided as a structure including, for example, a worm shaft(not shown), a worm wheel (not shown), and the drive shaft 1390.

The worm shaft may be integrally formed with a rotation shaft of themotor and may rotate the worm wheel by a worm formed on an outercircumferential surface thereof to be engaged with the worm wheel. Theworm wheel may linearly move the drive shaft 1390 by being connected tobe engaged with the drive shaft 1390, and the drive shaft 1390 isconnected to the hydraulic piston 1320 so that the hydraulic piston 1320may be slidably moved within the cylinder block 1310.

Explaining the above operations again, when the displacement of thebrake pedal 10 is detected by the pedal displacement sensor 11, thedetected signal is transferred to the electronic control unit, and theelectronic control unit drives the motor to rotate the worm shaft in onedirection. The rotational force of the worm shaft is transferred to thedrive shaft 1390 via the worm wheel, and the hydraulic piston 1320connected to the drive shaft 1390 moves forward in the cylinder block1310, thereby generating a hydraulic pressure in the first pressurechamber 1330.

Conversely, when the pressing force of the brake pedal 10 is released,the electronic control unit drives the motor to rotate the worm shaft inthe opposite direction. Accordingly, the worm wheel also rotates in theopposite direction, and the hydraulic piston 1320 connected to the driveshaft 1390 moves backward in the cylinder block 1310, thereby generatinga negative pressure in the first pressure chamber 1330.

The generation of a hydraulic pressure and negative pressure in thesecond pressure chamber 1340 may be implemented by operating opposite tothe above operations. That is, when the displacement of the brake pedal10 is detected by the pedal displacement sensor 11, the detected signalis transferred to the electronic control unit, and the electroniccontrol unit drives the motor to rotate the worm shaft in the oppositedirection. The rotational force of the worm shaft is transferred to thedrive shaft 1390 via the worm wheel, and the hydraulic piston 1320connected to the drive shaft 1390 moves backward within the cylinderblock 1310, thereby generating a hydraulic pressure in the secondpressure chamber 1340.

Conversely, when the pressing force of the brake pedal 10 is released,the electronic control unit drives the motor to rotate the worm shaft inone direction. Accordingly, the worm wheel also rotates in onedirection, and the hydraulic piston 1320 connected to the drive shaft1390 moves forward in the cylinder block 1310, thereby generating anegative pressure in the second pressure chamber 1340.

As such, the hydraulic pressure supply device 1300 may generate ahydraulic pressure or negative pressure in the first pressure chamber1330 and the second pressure chamber 1340, respectively, depending onthe rotation direction of the worm shaft by the operation of the motor,and whether a hydraulic pressure is transferred to the chambers toperform braking, or whether a negative pressure is generated in thechambers to release braking may be determined by controlling the valves.A detailed description thereof will be described later.

The power conversion unit according to the present embodiment is notlimited to any one structure as long as it may convert the rotationalmotion of the motor into the linear motion of the hydraulic piston 1320,and may include devices having various structures and manners.

The hydraulic pressure supply device 1300 may be hydraulically connectedto the reservoir 1100 by the dump controller 1800. The dump controller1800 may include a first dump flow path 1810 connecting the firstpressure chamber 1330 and the reservoir 1100, and a first bypass flowpath 1830 that is branched from the first dump flow path 1810 andrejoins the first dump flow path 1810.

A first dump check valve 1811 and a first dump valve 1831 forcontrolling the flow of the pressurized medium may be provided in thefirst dump flow path 1810 and the first bypass flow path 1830,respectively. The first dump check valve 1811 may be provided to allowonly the flow of the pressurized medium from the reservoir 1100 towardthe first pressure chamber 1330 and block the flow of the pressurizedmedium in the opposite direction. The first bypass flow path 1830 isconnected in parallel with respect to the first dump check valve 1811 inthe first dump flow path 1810, and the first dump valve 1831 forcontrolling the flow of the pressurized medium between the firstpressure chamber 1330 and the reservoir 1100 may be provided in thefirst bypass flow path 1830. In other words, the first bypass flow path1830 may bypass the first dump check valve 1811 on the first dump flowpath 1810 to connect a front end and a rear end of the first dump checkvalve 1811, and the first dump valve 1831 may be provided as abidirectional solenoid valve for controlling the flow of the pressurizedmedium between the first pressure chamber 1330 and the reservoir 1100.The first dump valve 1831 may be provided as a normally closed typesolenoid valve that operates to be opened when an electric signal isreceived from the electronic control unit in a normally closed state.

The hydraulic control unit 1400 may be provided to control a hydraulicpressure transferred to the respective wheel cylinders 20, and theelectronic control unit (ECU) is provided to control the hydraulicpressure supply device 1300 and various valves based on the hydraulicpressure information and pedal displacement information.

The hydraulic control unit 1400 may include a first hydraulic circuit1510 for controlling the flow of the hydraulic pressure to betransferred to first and second wheel cylinders 21 and 22 among the fourwheel cylinders, and a second hydraulic circuit 1520 for controlling theflow of the hydraulic pressure to be transferred to third and fourthwheel cylinders 23 and 24, and includes a plurality of flow paths andvalves to control the hydraulic pressure to be transferred from thehydraulic pressure supply device 1300 to the wheel cylinders 20.

The first hydraulic flow path 1401 is provided to be in communicationwith the first pressure chamber 1330 and may be branched into a secondhydraulic flow path 1402 and a third hydraulic flow path 1403. Also, thefourth hydraulic flow path 1404 is provided to be in communication withthe second pressure chamber 1340 and may be branched into a fifthhydraulic flow path 1405 and a sixth hydraulic flow path 1406.

The second hydraulic flow path 1402 and the third hydraulic flow path1403 branched from the first hydraulic flow path 1401 are provided to beconnected to the first hydraulic circuit and the second hydrauliccircuit, respectively. A first valve 1431 for controlling the flow ofthe pressurized medium may be provided in the second hydraulic flow path1402. The first valve 1431 may be provided as a check valve for allowingthe flow of the pressurized medium from the first pressure chambertoward the first hydraulic circuit, while blocking the flow of thepressurized medium in the opposite direction. Also, a second valve 1432for controlling the flow of the pressurized medium may be provided inthe third hydraulic flow path 1403, and the second valve 1432 may beprovided as a check valve for allowing the flow of the pressurizedmedium from the first pressure chamber toward the second hydrauliccircuit, while blocking the flow of the pressurized medium in theopposite direction.

The fifth hydraulic flow path 1405 and the sixth hydraulic flow path1406 branched from the fourth hydraulic flow path 1404 are provided tobe connected to the first hydraulic circuit and the second hydrauliccircuit, respectively. A third valve 1433 for controlling the flow ofthe pressurized medium may be provided in the fifth hydraulic flow path1405. The third valve 1433 may be provided as a check valve for allowingthe flow of the pressurized medium from the second pressure chambertoward the first hydraulic circuit, while blocking the flow of thepressurized medium in the opposite direction. Also, a fourth valve 1434for controlling the flow of the pressurized medium may be provided inthe sixth hydraulic flow path 1406, and the fourth valve 1434 may beprovided as a check valve for allowing the flow of the pressurizedmedium from the second pressure chamber toward the second hydrauliccircuit, while blocking the flow of the pressurized medium in theopposite direction.

The first hydraulic flow path 1401 may be provided by branching aseventh hydraulic flow path 1407 along with the second hydraulic flowpath 1402 and the third hydraulic flow path 1403. Also, the fourthhydraulic flow path 1404 may be provided by branching an eighthhydraulic flow path 1408 in addition to the fifth hydraulic flow path1405 and the sixth hydraulic flow path 1406. The seventh hydraulic flowpath 1407 and the eighth hydraulic flow path 1408 may join to form aninth hydraulic flow path 1409, and the ninth hydraulic flow path 1409may be again branched into a tenth hydraulic flow path 1410 connected tothe first hydraulic circuit and an eleventh hydraulic flow path 1411connected to the second hydraulic circuit.

A fifth valve 1435 for controlling the flow of the pressurized mediummay be provided in the seventh hydraulic flow path 1407. The fifth valve1435 may be provided as a bidirectional control valve for controllingthe flow of the pressurized medium transferred along the seventhhydraulic flow path 1407. The fifth valve 1435 may be provided as anormally closed type solenoid valve that operates to be opened when anelectric signal is received from the electronic control unit in anormally closed state.

A sixth valve 1436 for controlling the flow of the pressurized mediummay be provided in the eighth hydraulic flow path 1408. The sixth valve1436 may be provided as a bidirectional control valve for controllingthe flow of the pressurized medium transferred along the eighthhydraulic flow path 1408. Like the fifth valve 1435, the sixth valve1436 may be provided as a normally closed type solenoid valve thatoperates to be opened when an electric signal is received from theelectronic control unit in a normally closed state.

A seventh valve 1437 for controlling the flow of the pressurized mediummay be provided in the tenth hydraulic flow path 1410. The seventh valve1437 may be provided as a check valve for allowing the flow of thepressurized medium from the first hydraulic circuit toward the ninthhydraulic flow path 1409, while blocking the flow of the pressurizedmedium in the opposite direction. Also, an eighth valve 1438 forcontrolling the flow of the pressurized medium may be provided in theeleventh hydraulic flow path 1411, and the eighth valve 1438 may beprovided as a check valve for allowing the flow of the pressurizedmedium from the second hydraulic circuit toward the ninth hydraulic flowpath 1409, while blocking the flow of the pressurized medium in theopposite direction.

By the arrangement of the hydraulic flow paths and valves of thehydraulic control unit 1400 as described above, the hydraulic pressuregenerated in the first pressure chamber 1330 according to the forwardmovement of the hydraulic piston 1320 may be transferred to the firsthydraulic circuit 1510 by sequentially passing through the firsthydraulic flow path 1401 and the second hydraulic flow path 1402, andmay be transferred to the second hydraulic circuit 1520 by sequentiallypassing through the first hydraulic flow path 1401 and the thirdhydraulic flow path 1403. Also, the hydraulic pressure formed in thesecond pressure chamber 1340 according to the backward movement of thehydraulic piston 1320 may be transferred to the first hydraulic circuit1510 by sequentially passing through the fourth hydraulic flow path 1404and the fifth hydraulic flow path 1405, and may be transferred to thesecond hydraulic circuit 1520 by sequentially passing through the fourthhydraulic flow path 1404 and the sixth hydraulic flow path 1406.

Conversely, the negative pressure generated in the first pressurechamber 1330 according to the backward movement of the hydraulic piston1320 may recover the pressurized medium provided in the first hydrauliccircuit 1510 to the first pressure chamber 1330 by sequentially passingthrough the tenth hydraulic flow path 1410, the ninth hydraulic flowpath 1409, and the seventh hydraulic flow path 1407, and may recover thepressurized medium provided in the second hydraulic circuit 1520 to thefirst pressure chamber 1330 by sequentially passing through the eleventhhydraulic flow path 1411, the ninth hydraulic flow path 1409, and theseventh hydraulic flow path 1407. Also, the negative pressure generatedin the second pressure chamber 1340 according to the forward movement ofthe hydraulic piston 1320 may recover the pressurized medium provided inthe first hydraulic circuit 1510 to the first pressure chamber 1330 bysequentially passing through the tenth hydraulic flow path 1410, theninth hydraulic flow path 1409, and the eighth hydraulic flow path 1408,and may recover the pressurized medium provided in the second hydrauliccircuit 1520 to the first pressure chamber 1330 by sequentially passingthrough the eleventh hydraulic flow path 1411, the ninth hydraulic flowpath 1409, and the eighth hydraulic flow path 1408.

In addition, the negative pressure generated in the first pressurechamber 1330 according to the backward movement of the hydraulic piston1320 may supply the pressurized medium from the reservoir 1100 to thefirst pressure chamber 1330 through the first dump flow path 1810.

A detailed description of the transfer of the hydraulic pressure andnegative pressure by the arrangement of these hydraulic flow paths andvalves will be described later with reference to FIGS. 2 to 5.

The first hydraulic circuit 1510 of the hydraulic control unit 1400 maycontrol the hydraulic pressure in the first wheel cylinder 21 and thesecond wheel cylinder 22, which are two wheel cylinders 20 among thefour wheels RR, RL, FR, and FL, and the second hydraulic circuit 1520may control the hydraulic pressure in the third and fourth wheelcylinders 23 and 24 which are the other two wheel cylinders 20.

The first hydraulic circuit 1510 may receive the hydraulic pressurethrough the second hydraulic flow path 1402 and the fifth hydraulic flowpath 1405 and discharge the hydraulic pressure through the tenthhydraulic flow path 1410. To this end, as illustrated in FIG. 1, thesecond hydraulic flow path 1402, the fifth hydraulic flow path 1405, andthe tenth hydraulic flow path 1410 may be provided to be branched intotwo flow paths, which are connected to the first wheel cylinder 21 andthe second wheel cylinder 22, after joining. Also, the second hydrauliccircuit 1520 may receive the hydraulic pressure through the thirdhydraulic flow path 1403 and the fifth hydraulic flow path 1405 anddischarge the hydraulic pressure through the eleventh hydraulic flowpath 1411, and accordingly, as illustrated in FIG. 1, the thirdhydraulic flow path 1403, the fifth hydraulic flow path 1405, and theeleventh hydraulic flow path 1411 may be provided to be branched intotwo flow paths, which are connected to the third wheel cylinder 23 andthe fourth wheel cylinder 24, after joining. However, the connection ofthe hydraulic flow paths illustrated in FIG. 1, which is an example forhelping the understanding of the present disclosure, is not limitedthereto, and may be provided in various manners and structures as suchas cases in which the second hydraulic flow path 1402, the fifthhydraulic flow path 1405, and the tenth hydraulic flow path 1410 may beconnected to the first hydraulic circuit 1510 side, respectively, andindependently branched to be connected to the first wheel cylinder 21and the second wheel cylinder 22, and likewise, the third hydraulic flowpath 1403, the fifth hydraulic flow path 1405, and the eleventhhydraulic flow path 1411 may be connected to the second hydrauliccircuit 1520 side, respectively, and independently branched to beconnected to the third wheel cylinder 23 and the fourth wheel cylinder24.

The first and second hydraulic circuits 1510 and 1520 may include firstto fourth inlet valves 1511 a, 1511 b, 1521 a, and 1521 b, respectively,to control the flow and hydraulic pressure of the pressurized medium tobe transferred to the first to fourth wheel cylinders 21 to 24. Thefirst to fourth inlet valves 1511 a, 1511 b, 1521 a, and 1521 b aredisposed on upstream sides of the first to fourth wheel cylinders 20,respectively, and may be provided as a normally open type solenoid valvethat operates to be closed when an electric signal is received from theelectronic control unit in a normally open state.

The first and second hydraulic circuits 1510 and 1520 may include firstto fourth check valves 1513 a, 1513 b, 1523 a, and 1523 b provided to beconnected in parallel with respect to the first to fourth inlet valves1511 a, 1511 b, 1521 a, and 1521 b. The check valves 1513 a, 1513 b,1523 a, and 1523 b may be provided in the bypass flow paths that connectfront sides and rear sides of the first to fourth inlet valves 1511 a,1511 b, 1521 a, and 1521 b on the first and second hydraulic circuits1510 and 1520, and may allow only the flow of pressurized medium fromeach of the wheel cylinders 20 to the hydraulic pressure supply device1300, while blocking the flow of the pressurized medium from thehydraulic pressure supply device 1300 to the wheel cylinders 20. By thefirst to fourth check valves 1513 a, 1513 b, 1523 a, and 1523 b, thehydraulic pressure of the pressurized medium applied to each of thewheel cylinders 20 may be quickly released, and even when the first tofourth inlet valves 1511 a, 1511 b, 1521 a, and 1521 b do not operatenormally, the hydraulic pressure of the pressurized medium applied tothe wheel cylinders 20 may be smoothly returned to the hydraulicpressure providing unit.

The first hydraulic circuit 1510 may include first and second outletvalves 1512 a and 1512 b for controlling the flow of the pressurizedmedium discharged from the first and second wheel cylinders 21 and 22 toimprove performance when braking of the first and second wheel cylinders21 and 22 is released. The first and second outlet valves 1512 a and1512 b are provided on discharge sides of the first and second wheelcylinders 21 and 22, respectively, to control the flow of thepressurized medium transferred from the first and second wheel cylinders21 and 22 to the reservoir 1100. The first and second outlet valves 1512a and 1512 b may be provided as normally closed type solenoid valvesthat operate to be opened when an electric signal is received from theelectronic control unit in a normally closed state. In an ABS brakingmode of the vehicle, the first and second outlet valves 1512 a and 1512b may selectively release the hydraulic pressure of the pressurizedmedium applied to the first and second wheel cylinders 21 and 22 andtransfer the released hydraulic pressure of the pressurized medium tothe reservoir 1100 side.

The second backup flow path 1620, which will be described later, may bebranched and connected to the third and fourth wheel cylinders 23 and 24of the second hydraulic circuit 1520, and the at least one second cutvalve 1621 may be provided in the second backup flow path 1620 tocontrol the flow of the pressurized medium between the third and fourthwheel cylinders 23 and 24 and the integrated master cylinder 1200.

The electronic brake system 1000 according to the present embodiment mayinclude the first and second backup flow paths 1610 and 1620 and theauxiliary backup flow path 1630 to implement braking by directlysupplying the pressurized medium discharged from the integrated mastercylinder 1200 to the wheel cylinders 20 when the normal operation isimpossible due to a device failure or the like. A mode in which thehydraulic pressure in the integrated master cylinder 1200 is directlytransferred to the wheel cylinders 20 is referred to as an abnormaloperation mode, that is, a fallback mode.

The first backup flow path 1610 may be provided to connect the masterchamber 1220 a of the integrated master cylinder 1200 and the firsthydraulic circuit 1510, and the second backup flow path 1620 may beprovided to connect the first simulation chamber 1230 a of theintegrated master cylinder 1200 and the second hydraulic circuit 1520.The auxiliary backup flow path 1630 is provided to connect the secondsimulation chamber 1240 a of the integrated master cylinder 1200 and thesecond backup flow path 1620.

Specifically, the first backup flow path 1610 may have one end connectedto the master chamber 1220 a and the other end connected between thefirst inlet valve 1511 a and the first outlet valve 1512 a on the firsthydraulic circuit 1510, and the second backup flow path 1620 may haveone end connected to the first simulation chamber 1230 a and the otherend branched and connected to downstream sides of the third and fourthinlet valves 1521 a and 1521 b on the second hydraulic circuit 1520.Although FIG. 1 illustrates that the first backup flow path 1610 isconnected between the first inlet valve 1511 a and the first outletvalve 1512 a, the first backup flow path 1610 may be branched andconnected to at least one of upstream sides of the first outlet valve1512 a and the second outlet valve 1512 b. The auxiliary backup flowpath 1630 has one end connected to the second simulation chamber 1240 aand the other end provided to join the second backup flow path 1620, sothat the pressurized medium accommodated in the second simulationchamber 1240 a may be transferred to the second backup flow path 1620.

The first cut valve 1611 for controlling bidirectional flows of thepressurized medium may be provided in the first backup flow path 1610,and the at least one second cut valve 1621 for controlling bidirectionalflows of the pressurized medium may be provided in the second backupflow path 1620. The first cut valve 1611 and the second cut valve 1621may be provided as normally open type solenoid valves that operate to beclosed when a closing signal is received from the electronic controlunit in a normally open state.

As illustrated in FIG. 1, a pair of the second cut valves 1621 may beprovided on the third wheel cylinder 23 and the fourth wheel cylinder24, respectively, and may selectively release the hydraulic pressure ofthe pressurized medium applied to the third wheel cylinder 23 and thefourth wheel cylinder 24 in the ABS braking mode of the vehicle so thatthe released hydraulic pressure of the pressurized medium may bedischarged to the reservoir 1100 side by sequentially passing throughthe second backup flow path 1620, the first simulation chamber 1230 a,and the simulation flow path 1260.

An inspection valve 1631 for controlling bidirectional flows of thepressurized medium is provided in the auxiliary backup flow path 1630,and the inspection valve 1631 may be provided as a normally open typesolenoid valve that operates to be closed when a closing signal isreceived from the electronic control unit in a normally open state. Theinspection valve 1631 may be closed in the normal operation of theelectronic brake system 1000 to seal the second simulation chamber 1240a, and may be closed in an inspection mode of inspecting whether theintegrated master cylinder 1200 or the simulator valve 1261 has a leak.A detailed description thereof will be provided later.

Accordingly, when the first and second cut valves 1621 are closed, thepressurized medium in the integrated master cylinder 1200 may beprevented from being directly transferred to the wheel cylinders 20, andat the same time the hydraulic pressure provided from the hydraulicpressure supply device 1300 may be supplied to the first and secondhydraulic circuits 1510 and 1520 side through the hydraulic control unit1400, and when the first and second cut valves 1611 and 1612 andinspection valve 1631 are opened, the pressurized medium pressurized inthe integrated master cylinder 1200 may be directly supplied to thefirst and second hydraulic circuits 1510 and 1520 side through the firstand second backup flow paths 1620 and the auxiliary backup flow path1630, thereby performing braking.

The electronic brake system 1000 according to the present embodiment mayinclude a pressure sensor PS to detect a hydraulic pressure in at leastone of the first hydraulic circuit 1510 and the second hydraulic circuit1520. The drawing illustrates that the pressure sensor PS is provided inthe second hydraulic circuit 1520 side, but the pressure sensor is notlimited to the above position and number, and as long as the hydraulicpressures in the hydraulic circuits and the integrated master cylinder1200 may be detected, the pressure sensor may be provided in variouspositions and in various numbers.

Hereinafter, operation methods of the electronic brake system 1000according to the first embodiment of the present disclosure will bedescribed.

The operation of the electronic brake system 1000 according to thepresent embodiment may include the normal operation mode in whichvarious devices and valves operate normally without failure ormalfunction, the abnormal operation mode (fallback mode) in whichvarious devices and valves operate abnormally by failure or malfunction,and the inspection mode of inspecting whether a leak occurs in theintegrated master cylinder 1200 or the simulation valve 1261.

First, the normal operation mode among the operating methods of theelectronic brake system 1000 according to the present embodiment will bedescribed.

The normal operation mode of the electronic brake system 1000 accordingto the present embodiment may be divided into a first braking mode and asecond braking mode as the hydraulic pressure transferred from thehydraulic pressure supply device 1300 to the wheel cylinders 20increases. Specifically, in the first braking mode, the hydraulicpressure by the hydraulic pressure supply device 1300 may be primarilyprovided to the wheel cylinders 20, and in the second braking mode, thehydraulic pressure by the hydraulic pressure supply device 1300 may besecondarily provided to the wheel cylinders 20 to transfer a higherbraking pressure than in the first braking mode.

The first and second braking modes may be changed by changing theoperations of the hydraulic pressure supply device 1300 and thehydraulic control unit 1400. The hydraulic pressure supply device 1300may provide a sufficiently high hydraulic pressure of the pressurizedmedium without a high specification motor 120 by utilizing the first andsecond braking modes, and furthermore, may prevent unnecessary loadsapplied to the motor. Therefore, a stable braking force may be securedwhile reducing the cost and weight of the brake system, and durabilityand operational reliability of the devices may be improved.

FIG. 2 is a hydraulic circuit diagram illustrating that the electronicbrake system 1000 according the present disclosure performs the firstbraking mode.

Referring to FIG. 2, when the driver depresses the brake pedal 10 at thebeginning of braking, the motor (not shown) operates to rotate in onedirection, the rotational force of the motor is transferred to thehydraulic pressure providing unit by the power conversion unit, and thehydraulic piston 1320 of the hydraulic pressure providing unit movesforward, thereby generating a hydraulic pressure in the first pressurechamber 1330. The hydraulic pressure discharged from the first pressurechamber 1330 is transferred to the respective wheel cylinders 20 throughthe hydraulic control unit 1400, the first hydraulic circuit 1510 andthe second hydraulic circuit 1520, thereby generating a braking force.

Specifically, a part of the hydraulic pressure generated in the firstpressure chamber 1330 is primarily transferred to the first wheelcylinder 21 and the second wheel cylinder 22 provided in the firsthydraulic circuit 1510 by sequentially passing through the firsthydraulic flow path 1401 and the second hydraulic flow path 1402. Atthis time, as the first valve 1431 is provided as a check valve forallowing only the flow of the pressurized medium from the first pressurechamber 1330 toward the first hydraulic circuit 1510 side, the hydraulicpressure of the pressurized medium may be smoothly transferred to thefirst and second wheel cylinders 21 and 22. Also, the first inlet valve1511 a and the second inlet valve 1511 b provided in the first hydrauliccircuit 1510 are maintained in an open state, and the first outlet valve1512 a and the second outlet valve 1512 b are maintained in a closedstate, thereby preventing the hydraulic pressure of the pressurizedmedium from leaking into the reservoir 1100 side.

The hydraulic pressure generated in the first pressure chamber 1330 isprimarily transferred to the third and fourth wheel cylinders 23 and 24provided in the second hydraulic circuit 1520 by sequentially passingthrough the first hydraulic flow path 1401 and the third hydraulic flowpath 1403. As described above, as the second valve 1432 is provided as acheck valve for allowing only the flow of the pressurized medium fromthe first pressure chamber 1330 toward the second hydraulic circuit 1520side, the hydraulic pressure of the pressurized medium may be smoothlytransferred to the third and fourth wheel cylinders 23 and 24. Also, thethird inlet valve 1521 a and the fourth inlet valve 1521 b provided inthe second hydraulic circuit 1520 are maintained in an open state, and asecond cut valve 1622 is maintained in a closed state, therebypreventing the hydraulic pressure of the pressurized medium from leakinginto the second backup flow path 1620 side.

In the first braking mode, a part of the hydraulic pressure of thepressurizing medium generated in the first pressure chamber 1330 may besupplied to the second pressure chamber 1340. As the hydraulic piston1320 moves forward to generate a hydraulic pressure in the first brakingmode, a part of the pressurization medium accommodated in the firstpressure chamber 1330 is supplied to and filled in the second pressurechamber 1340, so that the second braking mode, which will be describedlater, may be prepared. To this end, in the first braking mode, thefifth valve 1435 and the sixth valve 1436 are operated to open, so thatthe flow of the pressurized medium through the seventh hydraulic flowpath 1407 and the eighth hydraulic flow path 1408 may be allowed. Inother words, a part of the hydraulic pressure generated in the firstpressure chamber 1330 may be supplied to the second pressure chamber1340 by sequentially passing through the first hydraulic flow path 1401,the seventh hydraulic flow path 1407, the eighth hydraulic flow path1408, and the fourth hydraulic flow path 1404.

The first dump valve 1831 provided in the first bypass flow path 1830 ismaintained in a closed state, thereby preventing the hydraulic pressureof the pressurized medium generated in the first pressure chamber 1330from leaking into the reservoir 1100 side.

In the first braking mode in which braking of the wheel cylinders 20 isperformed by the hydraulic pressure supply device 1300, the first cutvalve 1611 and the second cut valve 1621 provided in the first backupflow path 1610 and the second backup flow path 1620, respectively, areswitched to be closed, so that the pressurized medium discharged fromthe integrated master cylinder 1200 is prevented from being transferredto the wheel cylinders 20 side.

Specifically, because the first cut valve 1611 is closed when a pressingforce is applied to the brake pedal 10, the master chamber 1220 a issealed. Therefore, as a pressing force is applied to the brake pedal 10,the pressurized medium accommodated in the master chamber 1220 a ispressurized to generate a hydraulic pressure, the hydraulic pressure ofthe pressurized medium generated in the master chamber 1220 a istransferred to the front surface (right side of FIG. 2) of the firstsimulation piston 1230, and the simulator valve 1261 is opened in thenormal operation mode, so that a displacement occurs in the firstsimulation piston 1230. On the other hand, because the inspection valve1631 is closed in the normal operation mode of the electronic brakesystem 1000, the second simulation chamber 1240 a is sealed so that nodisplacement occurs in the second simulation piston 1240, and thus theelastic member 1250 is compressed by the displacement of the firstsimulation piston 1230, and the elastic restoring force by thecompression of the elastic member 1250 is provided to the driver as apedal feeling. At this time, the pressurized medium accommodated in thefirst simulation chamber 1230 a is discharged to the reservoir 1100through the simulation flow path 1260.

The electronic brake system 1000 according to the present embodiment mayswitch from the first braking mode to the second braking mode shown inFIG. 3 when a braking pressure higher than that in the first brakingmode is to be provided.

FIG. 3 is a hydraulic circuit diagram illustrating that the electronicbrake system 1000 according to the present embodiment performs thesecond braking mode, and referring to FIG. 3, when a displacement or anoperating speed of the brake pedal 10 detected by the pedal displacementsensor 11 is higher than a preset level or a hydraulic pressure detectedby the pressure sensor is higher than a preset level, the electroniccontrol unit may switch from the first braking mode to the secondbraking mode by determining that a higher braking pressure is required.

When the first braking mode is switched to the second braking mode, themotor operates to rotate in the other direction, and the rotationalforce of the motor is transferred to the hydraulic pressure providingunit by the power conversion unit so that the hydraulic piston 1320moves backward, thereby generating a hydraulic pressure in the secondpressure chamber 1340. The hydraulic pressure discharged from the secondpressure chamber 1340 is transferred to the respective wheel cylinders20 through the hydraulic control unit 1400, the first hydraulic circuit1510, and the second hydraulic circuit 1520, thereby generating abraking force.

Specifically, the hydraulic pressure generated in the second pressurechamber 1340 is secondarily transferred to the first wheel cylinder 21and the second wheel cylinder 22 provided in the first hydraulic circuit1510 by sequentially passing through the fourth hydraulic flow path 1404and the fifth hydraulic flow path 1405. At this time, as the third valve1433 provided in the fifth hydraulic flow path 1405 is provided as acheck valve for allowing only the flow of the pressurized medium fromthe second pressure chamber 1340 toward the first hydraulic circuit 1510side, the hydraulic pressure of the pressurized medium may be smoothlytransferred to the first wheel cylinder 21 and the second wheel cylinder22. The first inlet valve 1511 a and the second inlet valve 1511 bprovided in the first hydraulic circuit 1510 are maintained in the openstate, and the first outlet valve 1512 a and the second outlet valve1512 b are maintained in the closed state, thereby preventing thehydraulic pressure of the pressurized medium from leaking into thereservoir 1100 side.

Also, the hydraulic pressure generated in the second pressure chamber1340 is secondarily transferred to the third wheel cylinder 23 and thefourth wheel cylinder 24 provided in the second hydraulic circuit 1520by sequentially passing through the fourth hydraulic flow path 1404 andthe sixth hydraulic flow path 1406. As the fourth valve 1434 provided inthe sixth hydraulic flow path 1406 is provided as a check valve forallowing only the flow of the pressurized medium from the secondpressure chamber 1340 toward the second hydraulic circuit 1520 side, thehydraulic pressure of the pressurized medium may be smoothly transferredto the third wheel cylinder 23 and the fourth wheel cylinder 24. Thethird inlet valve 1521 a and the fourth inlet valve 1521 b provided inthe second hydraulic circuit 1520 are maintained in the open state, andthe second cut valve 1622 is maintained in the closed state, therebypreventing the hydraulic pressure of the pressurized medium from leakinginto the second backup flow path 1620 side.

In the second braking mode, as the fifth valve 1435 provided in theseventh hydraulic flow path 1407 is switched to a closed state, thehydraulic pressure of the pressurized medium generated in the secondpressure chamber 1340 may be prevented from leaking into the firstpressure chamber 1330, and the first pressure chamber 1330 may be filledwith the pressurized medium supplied from the reservoir 1100 through thefirst dump flow path 1810. In this case, the first dump valve 1831provided in the first bypass flow path 1830 is switched to an open stateas necessary, so that the flow of the pressurized medium from thereservoir 1100 toward the first pressure chamber 1330 may be allowed.

Hereinafter, an operation method of the electronic brake system 1000according to the present embodiment in which the braking is releasedfrom the normal operation mode will be described.

FIG. 4 is a hydraulic circuit diagram illustrating that the hydraulicpiston 1320 of the electronic brake system 1000 according to the presentembodiment moves forward to release the second braking mode.

Referring to FIG. 4, when the pressing force applied to the brake pedal10 is released, the motor generates a rotational force in one directionand transfers the rotational force to the power conversion unit, and thepower conversion unit moves the hydraulic piston 1320 forward.Accordingly, the hydraulic pressure in the first pressure chamber 140 isreleased, and at the same time, a negative pressure may be generated, sothat the pressurized medium in the wheel cylinders 20 may be transferredto the second pressure chamber 1340.

Specifically, the hydraulic pressure of the pressurized medium appliedto the first wheel cylinder 21 and the second wheel cylinder 22 providedin the first hydraulic circuit 1510 is recovered to the second pressurechamber 1340 by sequentially passing through the tenth hydraulic flowpath 1410, the ninth hydraulic flow path 1409, the eighth hydraulic flowpath 1408, and the fourth hydraulic flow path 1404. At this time, thesixth valve 1436 is opened to allow the flow of the pressurized mediumthrough the eighth hydraulic flow path 1408, and the fifth valve 1435 isclosed to prevent the recovered pressurized medium from leaking into thefirst pressure chamber 1330. Also, the first inlet valve 1511 a and thesecond inlet valve 1511 b provided in the first hydraulic circuit 1510are maintained in the open state, and the first outlet valve 1512 a andthe second outlet valve 1512 b are maintained in the closed state.

Also, the hydraulic pressure of the pressurized medium applied to thethird wheel cylinder 23 and the fourth wheel cylinder 24 provided in thesecond hydraulic circuit 1520 by the negative pressure generated in thesecond pressure chamber 1340 is recovered to the second pressure chamber1340 by sequentially passing through the eleventh hydraulic flow path1411, the ninth hydraulic flow path 1409, the eighth hydraulic flow path1408, and the fourth hydraulic flow path 1404. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are provided in the open state. When the secondbraking mode is released, the first dump valve 1831 may be opened tosmoothly implement the forward movement of the hydraulic piston 1320.

After the releasing of the second braking mode is completed, it may beswitched to the releasing operation of the first braking modeillustrated in FIG. 5 in order to completely release the brakingpressure applied to the wheel cylinders 20.

FIG. 5 is a hydraulic circuit diagram illustrating that the hydraulicpiston 1320 of the electronic brake system 1000 according to the presentembodiment moves backward to release the first braking mode.

Referring to FIG. 5, when the pressing force applied to the brake pedal10 is released, the motor generates a rotational force in the otherdirection and transfers the rotational force to the power conversionunit, and the power conversion unit moves the hydraulic piston 1320backward. Accordingly, a negative pressure may be generated in the firstpressure chamber 1330, so that the pressurized medium in the wheelcylinders 20 may be transferred to the first pressure chamber 1330.

Specifically, the hydraulic pressure in the first and second wheelcylinders 21 and 22 provided in the first hydraulic circuit 1510 isrecovered to the first pressure chamber 1330 by sequentially passingthrough the tenth hydraulic flow path 1410, the ninth hydraulic flowpath 1409, the seventh hydraulic flow path 1407, and the first hydraulicflow path 1401. At this time, the fifth valve 1436 is opened to allowthe flow of the pressurized medium through the seventh hydraulic flowpath 1407, and the first dump valve 1831 is closed to effectivelygenerate a negative pressure in the first pressure chamber 1330. Inaddition, in order to enable the hydraulic piston 1320 to quickly andsmoothly move backward, the pressurized medium accommodated in thesecond pressure chamber 1340 is transferred to the first pressurechamber 1330 by sequentially passing through the fourth hydraulic flowpath 1404, the eighth hydraulic flow path 1408, the seventh hydraulicflow path 1407, and the first hydraulic flow path 1401, and to this end,the sixth valve 1436 provided in the eighth hydraulic flow path 1408 isswitched to an open state. The first inlet valve 1511 a and the secondinlet valve 1511 b provided in the first hydraulic circuit 1510 aremaintained in the open state, and the first outlet valve 1512 a and thesecond outlet valve 1512 b are maintained in the closed state.

Also, the hydraulic pressure of the pressurized medium applied to thethird wheel cylinder 23 and the fourth wheel cylinder 24 provided in thesecond hydraulic circuit 1520 by the negative pressure generated in thefirst pressure chamber 1330 is recovered to the first pressure chamber1330 by sequentially passing through the eleventh hydraulic flow path1411, the ninth hydraulic flow path 1409, the seventh hydraulic flowpath 1407, and the first hydraulic flow path 1401. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are provided in the open state.

Hereinafter, an operation method in a case where the electronic brakesystem 1000 according to the present embodiment does not operatenormally, that is, in the fallback mode will be described.

FIG. 6 is a hydraulic circuit diagram illustrating the operation of theelectronic brake system 1000 according to the present embodiment in theabnormal operation mode (fallback mode) when a normal operation isimpossible due to a device failure or the like.

Referring to FIG. 6, in the abnormal operation mode, each of the valvesis controlled to an initial braking state which is a non-operationalstate. At this time, when the driver depresses the brake pedal 10, themaster piston 1220 connected to the brake pedal 10 moves forward togenerate a displacement. Because the first cut valve 1611 is provided inthe open state in the non-operational state, by the forward movement ofthe master piston 1220, the pressurized medium accommodated in themaster chamber 1220 a is transferred to the first wheel cylinder 21 andthe second wheel cylinder 22 of the first hydraulic circuit 1510 alongthe first backup flow path 1610, thereby performing braking.

Also, the pressurized medium accommodated in the master chamber 1220 amoves the first simulation piston 1230 forward to generate adisplacement, so that the pressurized medium accommodated in the firstsimulation chamber 1230 a is transferred to the third wheel cylinder 23and the fourth wheel cylinder 24 of the second hydraulic circuit 1520along the second backup flow path 1620, thereby performing braking. Atthe same time, the second simulation piston 1240 also generates adisplacement by moving forward due to the displacement of the firstsimulation piston 1230, so that the pressurized medium accommodated inthe second simulation chamber 1240 a may be provided to the secondhydraulic circuit 1520 by joining into the second backup flow path 1620along the auxiliary backup flow path 1630. At this time, because thesimulator valve 1261 is provided in a closed state in thenon-operational state, the pressurized medium accommodated in the firstsimulation chamber 1230 a may be transferred to the second backup flowpath 1620 without being discharged to the reservoir 1100, and at thesame time, may generate a hydraulic pressure for moving the secondsimulation piston 1240 forward, and because the inspection valve 1631and the second cut valve 1621 are provided in an open state, thepressurized medium accommodated in the first simulation chamber 1230 aand the second simulation chamber 1240 a may be transferred to thesecond backup flow path 1620.

Hereinafter, the inspection mode of the electronic brake system 1000according to the first embodiment of the present disclosure will bedescribed.

FIG. 7 is a hydraulic circuit diagram illustrating the inspection modeof the electronic brake system 1000 according to the first embodiment ofthe present disclosure performs, and referring to FIG. 7, the electronicbrake system 1000 according to the present embodiment may perform theinspection mode of inspecting whether the integrated master cylinder1200 or the simulator valve 1261 has a leak. When the inspection mode isperformed, the electronic control unit controls to supply the hydraulicpressure generated from the hydraulic pressure supply device 1300 to thefirst simulation chamber 1230 a of the integrated master cylinder 1200.

Specifically, in a state in which each of the valves is controlled tothe initial braking state, which is a non-operational state, theelectronic control unit operates to move the hydraulic piston 1320forward, so that a hydraulic pressure is generated in the first pressurechamber 1330, the inspection valve 1631 and the first cut valve 1611 areswitched to a closed state, and the second cut valve 1621 is maintainedin the open state. Accordingly, the hydraulic pressure generated in thefirst pressure chamber 1330 is transferred to the second hydrauliccircuit 1520 side by sequentially passing through the first hydraulicflow path 1401 and the third hydraulic flow path 1403, the third inletvalve 1521 a and the fourth inlet valve 1521 b are maintained in anormally open state, and the pressurized medium transferred to thesecond hydraulic circuit 1520 is introduced into the first simulationchamber 1230 a through the second backup flow path 1620. At this time,the simulator valve 1261 is maintained in the closed state to induce thefirst simulation chamber 1230 a to be in a sealed state.

In order to quickly perform the inspection mode, the first inlet valve1511 a and the second inlet valve 1511 b provided in the first hydrauliccircuit 1510 may be switched to the closed state.

In this state, an expected hydraulic pressure value of the pressurizedmedium to be generated by the displacement of the hydraulic piston 1320is compared with a hydraulic pressure value in the second hydrauliccircuit 1520 or the first simulation chamber 1230 a measured by thepressure sensor PS, so that a leak in the integrated master cylinder1200 or the simulator valve 1261 may be diagnosed. Specifically, theexpected hydraulic pressure value calculated based on a displacementamount of the hydraulic piston 1320 or a rotation angle measured by amotor control sensor (not shown) is compared with an actual hydraulicpressure value measured by the pressure sensor PS, and when the twohydraulic pressure values match, it may be determined that there is noleak in the integrated master cylinder 1200 or the simulator valve 1261.On the other hand, when the actual hydraulic pressure value measured bythe pressure sensor PS is lower than the expected hydraulic pressurevalue calculated based on the displacement amount of the hydraulicpiston 1320 or the rotation angle measured by the motor control sensor(not shown), because this is due to the loss of a part of the hydraulicpressure of the pressurized medium applied to the first simulationchamber 1230 a, it is determined that there is a leak in the integratedmaster cylinder 1200 or the simulator valve 1261, and this leak may benotified to the driver.

Hereinafter, an electronic brake system 2000 according to a secondembodiment of the present disclosure will be described.

FIG. 8 is a hydraulic circuit diagram illustrating the electronic brakesystem 2000 according to the second embodiment of the presentdisclosure, and referring to FIG. 8, a dump controller 2800 according tothe second embodiment of the present disclosure may include a seconddump flow path 2820 connecting the second pressure chamber 1340 and thereservoir 1100, and a second bypass flow path 2840 branched and thenrejoined on the second dump flow path 2820.

Because except for additional explanations with separate referencenumerals, the following description of the electronic brake system 2000according to the second embodiment of the present disclosure is the sameas the above description of the electronic brake system 1000 accordingto the first embodiment of the present disclosure, in order to preventredundant description, a description thereof will be omitted.

A second dump check valve 2821 and a second dump valve 2841 forcontrolling the flow of the pressurized medium may be provided in thesecond dump flow path 2820 and the second bypass flow path 2840,respectively. The second dump check valve 2821 may be provided to allowonly the flow of the pressurized medium from the reservoir 1100 towardthe second pressure chamber 1330 and block the flow of the pressurizedmedium in the opposite direction. The second bypass flow path 2840 isconnected in parallel with respect to the second dump check valve 2821in the second dump flow path 2820, and the second dump valve 2841 forcontrolling the flow of the pressurized medium between the secondpressure chamber 1330 and the reservoir 1100 may be provided in thesecond bypass flow path 2840. In other words, the second bypass flowpath 2840 may bypass the second dump check valve 2821 on the second dumpflow path 2820 to connect a front end and a rear end of the second dumpcheck valve 2821, and the second dump valve 2841 may be provided as abidirectional solenoid valve for controlling the flow of the pressurizedmedium between the second pressure chamber 1330 and the reservoir 1100.The second dump valve 2841 may be provided as a normally open typesolenoid valve that operates to be closed when an electric signal isreceived from the electronic control unit in a normally open state.

Hereinafter, operation methods of the electronic brake system 2000according to the second embodiment of the present disclosure will bedescribed.

The operation of the electronic brake system 2000 according to thesecond embodiment of the present disclosure may include the normaloperation mode in which various devices and valves operate normallywithout failure or malfunction, the abnormal operation mode (fallbackmode) in which various devices and valves operate abnormally by failureor malfunction, and the inspection mode of inspecting whether a leakoccurs in the integrated master cylinder 1200 or the simulation valve1261.

The normal operation mode of the electronic brake system 2000 accordingto the present embodiment may be divided into a first braking mode to athird braking mode as the hydraulic pressure transferred from thehydraulic pressure supply device 1300 to the wheel cylinders 20increases. Specifically, in the first braking mode, the hydraulicpressure by the hydraulic pressure supply device 1300 may be primarilyprovided to the wheel cylinders 20, in the second braking mode, thehydraulic pressure by the hydraulic pressure supply device 1300 may besecondarily provided to the wheel cylinders 20 to transfer a higherbraking pressure than in the first braking mode, and in the thirdbraking mode, the hydraulic pressure by the hydraulic pressure supplydevice 1300 may be thirdly provided to the wheel cylinders 20 totransfer a higher braking pressure than in the second braking mode.

The first to third braking modes may be changed by changing theoperations of the hydraulic pressure supply device 1300 and thehydraulic control unit 1400. The hydraulic pressure supply device 1300may provide a sufficiently high hydraulic pressure of the pressurizedmedium without a high specification motor 120 by utilizing the first tothird braking modes, and furthermore, may prevent unnecessary loadsapplied to the motor. Therefore, a stable braking force may be securedwhile reducing the cost and weight of the brake system, and durabilityand operational reliability of the devices may be improved.

FIG. 9 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure performs the first braking mode.

Referring to FIG. 9, when the driver depresses the brake pedal 10 at thebeginning of braking, the motor (not shown) operates to rotate in onedirection, the rotational force of the motor is transferred to thehydraulic pressure providing unit by the power conversion unit, and thehydraulic piston 1320 of the hydraulic pressure providing unit movesforward, thereby generating a hydraulic pressure in the first pressurechamber 1330. The hydraulic pressure discharged from the first pressurechamber 1330 is transferred to the respective wheel cylinders 20 throughthe hydraulic control unit 1400, the first hydraulic circuit 1510 andthe second hydraulic circuit 1520, thereby generating a braking force.

Specifically, the hydraulic pressure generated in the first pressurechamber 1330 is primarily transferred to the first wheel cylinder 21 andthe second wheel cylinder 22 provided in the first hydraulic circuit1510 by sequentially passing through the first hydraulic flow path 1401and the second hydraulic flow path 1402. At this time, as the firstvalve 1431 is provided as a check valve for allowing only the flow ofthe pressurized medium from the first pressure chamber 1330 toward thefirst hydraulic circuit 1510 side, the hydraulic pressure of thepressurized medium may be smoothly transferred to the first wheelcylinder 21 and the second wheel cylinder 22. Also, the first inletvalve 1511 a and the second inlet valve 1511 b provided in the firsthydraulic circuit 1510 are maintained in the open state, and the firstoutlet valve 1512 a and the second outlet valve 1512 b are maintained inthe closed state, thereby preventing the hydraulic pressure of thepressurized medium from leaking into the reservoir 1100 side.

The hydraulic pressure generated in the first pressure chamber 1330 isprimarily transferred to the third wheel cylinder 23 and the fourthwheel cylinder 24 provided in the second hydraulic circuit 1520 bysequentially passing through the first hydraulic flow path 1401 and thethird hydraulic flow path 1403. As described above, as the second valve1432 is provided as a check valve for allowing only the flow of thepressurized medium from the first pressure chamber 1330 toward thesecond hydraulic circuit 1520 side, the hydraulic pressure of thepressurized medium may be smoothly transferred to the third and fourthwheel cylinders 23 and 24. Also, the third inlet valve 1521 a and thefourth inlet valve 1521 b provided in the second hydraulic circuit 1520are maintained in the open state, and the second cut valve 1622 ismaintained in the closed state, thereby preventing the hydraulicpressure of the pressurized medium from leaking into the second backupflow path 1620 side.

In the first braking mode, the sixth valve 1436 is maintained in theclosed state to prevent the hydraulic pressure of the pressurized mediumgenerated in the first pressure chamber 1330 from leaking into thesecond pressure chamber 1340. Accordingly, the hydraulic pressure of thepressurizing medium generated in the first pressure chamber 1330 is allsupplied to the wheel cylinders 20, so that a rapid braking may beperformed. Also, as the first dump valve 1831 is maintained in theclosed state, the hydraulic pressure of the pressurized medium generatedin the first pressure chamber 1330 may be prevented from leaking to thereservoir 1100.

In the first braking mode, as the hydraulic piston 1320 moves forward,the second pressure chamber 1340 is filled with the pressurized mediumsupplied from the reservoir 1100 through the second dump flow path 2820and the second bypass flow path 2840, and thus the second braking mode,which will be described later, may be prepared. Because the second dumpcheck valve 2821 provided in the second dump flow path 2820 allows theflow of the pressurized medium from the reservoir 1100 toward the secondpressure chamber 1340, the pressurized medium may be supplied stably tothe second pressure chamber 1340, and the second dump valve 2841provided in the second bypass flow path 2840 is switched to an openstate so that the pressurized medium may be quickly supplied from thereservoir 1100 to the second pressure chamber 1340.

Because an operation of the integrated master cylinder 1200 of theelectronic brake system 2000 according to the second embodiment of thepresent disclosure in the first braking mode is same as the operation ofthe integrated master cylinder 1200 of the electronic brake systemaccording to the first embodiment in the first and second braking modesdescribed above, in order to prevent redundant description, adescription thereof will be omitted.

The electronic brake system 2000 according to the second embodiment ofthe present disclosure may switch from the first braking mode to thesecond braking mode shown in FIG. 10 when a braking pressure higher thanthat in the first braking mode is to be provided.

FIG. 10 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure performs the second braking mode, and referring to FIG. 10,when a displacement or an operating speed of the brake pedal 10 detectedby the pedal displacement sensor 11 is higher than the preset level or ahydraulic pressure detected by the pressure sensor is higher than thepreset level, the electronic control unit may switch from the firstbraking mode to the second braking mode by determining that a higherbraking pressure is required.

When the first braking mode is switched to the second braking mode, themotor operates to rotate in the other direction, and the rotationalforce of the motor is transferred to the hydraulic pressure providingunit by the power conversion unit so that the hydraulic piston 1320moves backward, thereby generating a hydraulic pressure in the secondpressure chamber 1340. The hydraulic pressure discharged from the secondpressure chamber 1340 is transferred to the respective wheel cylinders20 through the hydraulic control unit 1400, the first hydraulic circuit1510, and the second hydraulic circuit 1520, thereby generating abraking force.

Specifically, the hydraulic pressure generated in the second pressurechamber 1340 is secondarily transferred to the first wheel cylinder 21and the second wheel cylinder 22 provided in the first hydraulic circuit1510 by sequentially passing through the fourth hydraulic flow path 1404and the fifth hydraulic flow path 1405. At this time, as the third valve1433 provided in the fifth hydraulic flow path 1405 is provided as acheck valve for allowing only the flow of the pressurized medium fromthe second pressure chamber 1340 toward the first hydraulic circuit 1510side, the hydraulic pressure of the pressurized medium may be smoothlytransferred to the first and second wheel cylinders 21 and 22. The firstinlet valve 1511 a and the second inlet valve 1511 b provided in thefirst hydraulic circuit 1510 are maintained in the open state, and thefirst outlet valve 1512 a and the second outlet valve 1512 b aremaintained in the closed state, thereby preventing the hydraulicpressure of the pressurized medium from leaking into the reservoir 1100side.

Also, the hydraulic pressure generated in the second pressure chamber1340 is secondarily transferred to the third wheel cylinder 23 and thefourth wheel cylinder 24 provided in the second hydraulic circuit 1520by sequentially passing through the fourth hydraulic flow path 1404 andthe sixth hydraulic flow path 1406. As the fourth valve 1434 provided inthe sixth hydraulic flow path 1406 is provided as a check valve forallowing only the flow of the pressurized medium from the secondpressure chamber 1340 toward the second hydraulic circuit 1520 side, thehydraulic pressure of the pressurized medium may be smoothly transferredto the third and fourth wheel cylinders 23 and 24. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are maintained in the open state, and the secondcut valve 1622 is maintained in the closed state, thereby preventing thehydraulic pressure of the pressurized medium from leaking into thesecond backup flow path 1620 side.

In the second braking mode, the fifth valve 1435 is controlled to aclosed state, thereby preventing the hydraulic pressure of thepressurized medium generated in the second pressure chamber 1340 fromleaking into the first pressure chamber 1330. Also, as the second dumpvalve 2841 is switched to a closed state, the hydraulic pressure of thepressurized medium generated in the second pressure chamber 1340 may beprevented from leaking into the reservoir 1100 side.

In the second braking mode, as the hydraulic piston 1320 moves backward,the first pressure chamber 1330 is filled with the pressurized mediumsupplied from the reservoir 1100 through the first dump flow path 2810and the first bypass flow path 2830, and thus the third braking mode,which will be described later, may be prepared. Because the first dumpcheck valve 2811 provided in the first dump flow path 2810 allows theflow of the pressurized medium from the reservoir 1100 toward the firstpressure chamber 1330, the pressurized medium may be supplied stably tothe first pressure chamber 1330, and the first dump valve 1831 providedin the first bypass flow path 1830 is switched to the open state so thatthe pressurized medium may be quickly supplied from the reservoir 1100to the first pressure chamber 1330.

Because an operation of the integrated master cylinder 1200 in thesecond braking mode is same as the operation of the integrated mastercylinder 1200 of the electronic brake system according to the firstembodiment in the first and second braking modes described above, inorder to prevent redundant description, a description thereof will beomitted.

The electronic brake system 2000 according to the second embodiment ofthe present disclosure may switch from the second braking mode to thethird braking mode shown in FIG. 11 when a braking pressure higher thanthat in the second braking mode is to be provided.

FIG. 11 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure performs the third braking mode.

Referring to FIG. 11, when a displacement or an operating speed of thebrake pedal 10 detected by the pedal displacement sensor 11 is higherthan the preset level or a hydraulic pressure detected by the pressuresensor is higher than the preset level, the electronic control unit mayswitch from the second braking mode to the third braking mode bydetermining that a higher braking pressure is required.

When the second braking mode is switched to the third braking mode, themotor operates to rotate in one direction, and the rotational force ofthe motor is transferred to the hydraulic pressure providing unit by thepower conversion unit, and the hydraulic piston 1320 of the hydraulicpressure providing unit moves forward again, thereby generating ahydraulic pressure in the first pressure chamber 1330. The hydraulicpressure discharged from the first pressure chamber 1330 is transferredto the respective wheel cylinders 20 through a hydraulic control unit3400, the first hydraulic circuit 1510, and the second hydraulic circuit1520, thereby generating a braking force.

Specifically, a part of the hydraulic pressure generated in the firstpressure chamber 1330 is thirdly transferred to the first wheel cylinder21 and the second wheel cylinder 22 provided in the first hydrauliccircuit 1510 by sequentially passing through the first hydraulic flowpath 1401 and the second hydraulic flow path 1402. At this time, as thefirst valve 1431 is provided as a check valve for allowing only the flowof the pressurized medium from the first pressure chamber 1330 towardthe first hydraulic circuit 1510 side, the hydraulic pressure of thepressurized medium may be smoothly transferred to the first wheelcylinder 21 and the second wheel cylinder 22. Also, the first inletvalve 1511 a and the second inlet valve 1511 b provided in the firsthydraulic circuit 1510 are maintained in the open state, and the firstoutlet valve 1512 a and the second outlet valve 1512 b are maintained inthe closed state, thereby preventing the hydraulic pressure of thepressurized medium from leaking into the reservoir 1100 side.

The hydraulic pressure generated in the first pressure chamber 1330 isthirdly transferred to the third wheel cylinder 23 and the fourth wheelcylinder 24 provided in the second hydraulic circuit 1520 bysequentially passing through the first hydraulic flow path 1401 and thethird hydraulic flow path 1403. As described above, as the second valve1432 is provided as a check valve for allowing only the flow of thepressurized medium from the first pressure chamber 1330 toward thesecond hydraulic circuit 1520 side, the hydraulic pressure of thepressurized medium may be smoothly transferred to the third and fourthwheel cylinders 23 and 24. Also, the third inlet valve 1521 a and thefourth inlet valve 1521 b provided in the second hydraulic circuit 1520are maintained in the open state, and the second cut valve 1622 ismaintained in the closed state, thereby preventing the hydraulicpressure of the pressurized medium from leaking into the second backupflow path 1620 side.

Because the pressurized medium of a high pressure is provided in thethird braking mode, as the hydraulic piston 1320 moves forward, a forceof the hydraulic pressure in the first pressure chamber 1330 to move thehydraulic piston 1320 backward also increases, so that a load applied tothe motor increases rapidly. Accordingly, in the third braking mode, thefifth valve 1435 and the sixth valve 1436 are operated to open, therebyallowing the flow of the pressurized medium through the seventhhydraulic flow path 1407 and the eighth hydraulic flow path 1408. Inother words, a part of the hydraulic pressure generated in the firstpressure chamber 1330 is supplied to the second pressure chamber 1340 bysequentially passing through the first hydraulic flow path 1401, theseventh hydraulic flow path 1407, the eighth hydraulic flow path 1408,and the fourth flow path 1404, and through this, the first pressurechamber 1330 and the second pressure chamber 1340 communicate with eachother to synchronize the hydraulic pressure, so that the load applied tothe motor may be reduced and the durability and reliability of thedevices may be improved.

In the third braking mode, the first dump valve 1831 is switched to theclosed state, so that the hydraulic pressure of the pressurized mediumgenerated in the first pressure chamber 1330 may be prevented fromleaking into the reservoir 1100 along the first bypass flow path 1830,and the second dump valve 2841 is also controlled to be closed, so thatas a negative pressure is rapidly generated in the second pressurechamber 1340 by the forward movement of the hydraulic piston 1320, thepressurized medium provided from the first pressure chamber 1330 may besmoothly supplied.

Because an operation of the integrated master cylinder 1200 in the thirdbraking mode is same as the operation of the integrated master cylinder1200 of the electronic brake system according to the first embodiment inthe first and second braking modes described above, in order to preventredundant description, a description thereof will be omitted.

Hereinafter, an operation method of releasing the braking in the normaloperation mode of the electronic brake system 2000 according to thesecond embodiment of the present disclosure will be described.

FIG. 12 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure releases the third braking mode as the hydraulic piston 1320moves backward.

Referring to FIG. 12, when the pressing force applied to the brake pedal10 is released, the motor generates a rotational force in the otherdirection and transfers the rotational force to the power conversionunit, and the power conversion unit moves the hydraulic piston 1320backward. Accordingly, the hydraulic pressure in the first pressurechamber 1330 is released, and at the same time, a negative pressure maybe generated, so that the pressurized medium in the wheel cylinders 20may be transferred to the first pressure chamber 1330.

Specifically, the hydraulic pressure in the first wheel cylinder 21 andthe second wheel cylinder 22 and 22 provided in the first hydrauliccircuit 1510 is recovered to the first pressure chamber 1330 bysequentially passing through the tenth hydraulic flow path 1410, theninth hydraulic flow path 1409, the seventh hydraulic flow path 1407,and the first hydraulic flow path 1401. At this time, the fifth valve1436 is opened to allow the flow of the pressurized medium through theseventh hydraulic flow path 1407, and the first dump valve 1831 isclosed to effectively generate a negative pressure in the first pressurechamber 1330. In addition, in order to enable the hydraulic piston 1320to quickly and smoothly move backward, the pressurized mediumaccommodated in the second pressure chamber 1340 is transferred to thefirst pressure chamber 1330 by sequentially passing through the fourthhydraulic flow path 1404, the eighth hydraulic flow path 1408, theseventh hydraulic flow path 1407, and the first hydraulic flow path1401, and to this end, the sixth valve 1436 provided in the eighthhydraulic flow path 1408 is also switched to an open state. At thistime, the second dump valve 2841 may be controlled to the open state asnecessary. The first inlet valve 1511 a and the second inlet valve 1511b provided in the first hydraulic circuit 1510 are maintained in theopen state, and the first outlet valve 1512 a and the second outletvalve 1512 b are maintained in the closed state.

Also, the hydraulic pressure of the pressurized medium applied to thethird wheel cylinder 23 and the fourth wheel cylinder 24 provided in thesecond hydraulic circuit 1520 by the negative pressure generated in thefirst pressure chamber 1330 is recovered to the first pressure chamber1330 by sequentially passing through the eleventh hydraulic flow path1411, the ninth hydraulic flow path 1409, the seventh hydraulic flowpath 1407, and the first hydraulic flow path 1401. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are provided in the open state.

After the release of the third braking mode is completed, it may beswitched to a release operation of the second braking mode shown in FIG.13 in order to further lower the braking pressure in the wheelcylinders.

FIG. 13 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure releases the second braking mode as the hydraulic piston 1320moves forward.

Referring to FIG. 13, when the pressing force applied to the brake pedal10 is released, the motor generates a rotational force in one directionand transfers the rotational force to the power conversion unit, and thepower conversion unit moves the hydraulic piston 1320 forward.Accordingly, the hydraulic pressure in the first pressure chamber 140 isreleased, and at the same time, a negative pressure may be generated, sothat the pressurized medium in the wheel cylinders 20 may be transferredto the second pressure chamber 1340.

Specifically, the hydraulic pressure of the pressurized medium appliedto the first wheel cylinder 21 and the second wheel cylinder 22 providedin the first hydraulic circuit 1510 is recovered to the second pressurechamber 1340 by sequentially passing through the tenth hydraulic flowpath 1410, the ninth hydraulic flow path 1409, the eighth hydraulic flowpath 1408, and the fourth hydraulic flow path 1404. At this time, thesixth valve 1436 is opened to allow the flow of the pressurized mediumthrough the eighth hydraulic flow path 1408, and the fifth valve 1435 isclosed to prevent the recovered pressurized medium from leaking into thefirst pressure chamber 1330. Also, the first inlet valve 1511 a and thesecond inlet valve 1511 b provided in the first hydraulic circuit 1510are maintained in the open state, and the first outlet valve 1512 a andthe second outlet valve 1512 b are maintained in the closed state.

Also, the hydraulic pressure of the pressurized medium applied to thethird wheel cylinder 23 and the fourth wheel cylinder 24 provided in thesecond hydraulic circuit 1520 by the negative pressure generated in thesecond pressure chamber 1340 is recovered to the second pressure chamber1340 by sequentially passing through the eleventh hydraulic flow path1411, the ninth hydraulic flow path 1409, the eighth hydraulic flow path1408, and the fourth hydraulic flow path 1404. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are maintained in the open state. When the secondbraking mode is released, the first dump valve 1831 may be opened tosmoothly implement the forward movement of the hydraulic piston 1320,and the second dump valve 2841 may be switched to the closed state sothat a negative pressure may be quickly generated in the second pressurechamber 1330.

After the release of the second braking mode is completed, it may beswitched to the releasing operation of the first braking modeillustrated in FIG. 14 in order to completely release the brakingpressure applied to the wheel cylinders 20.

FIG. 14 is a hydraulic circuit diagram illustrating that the electronicbrake system 2000 according to the second embodiment of the presentdisclosure releases the first braking mode as the hydraulic piston 1320moves backward again.

Referring to FIG. 14, when the pressing force applied to the brake pedal10 is released, the motor generates a rotational force in the otherdirection and transfers the rotational force to the power conversionunit, and the power conversion unit moves the hydraulic piston 1320backward. Accordingly, a negative pressure may be generated in the firstpressure chamber 1330, so that the pressurized medium in the wheelcylinders 20 may be transferred to the first pressure chamber 1330.

Specifically, the hydraulic pressure in the first wheel cylinder 21 andthe second wheel cylinder 22 provided in the first hydraulic circuit1510 is recovered to the second pressure chamber 1340 by sequentiallypassing through the tenth hydraulic flow path 1410, the ninth hydraulicflow path 1409, the seventh hydraulic flow path 1407, and the firsthydraulic flow path 1401. At this time, the fifth valve 1435 is openedto allow the flow of the pressurized medium through the seventhhydraulic flow path 1407, and the sixth valve 1436 is closed to preventthe recovered pressurized medium from leaking into the second pressurechamber 1340. In addition, the first dump valve 1831 is operated to beclosed so that negative pressure is effectively generated in the firstpressure chamber 1330, and the second dump valve 2841 may be opened tofacilitate a smooth backward movement of the hydraulic piston 1320.Also, the first inlet valve 1511 a and the second inlet valve 1511 bprovided in the first hydraulic circuit 1510 are maintained in the openstate, and the first outlet valve 1512 a and the second outlet valve1512 b are maintained in the closed state.

Also, the hydraulic pressure of the pressurized medium applied to thethird wheel cylinder 23 and the fourth wheel cylinder 24 provided in thesecond hydraulic circuit 1520 by the negative pressure generated in thefirst pressure chamber 1330 is recovered to the first pressure chamber1330 by sequentially passing through the eleventh hydraulic flow path1411, the ninth hydraulic flow path 1409, the seventh hydraulic flowpath 1407, and the first hydraulic flow path 1401. The third inlet valve1521 a and the fourth inlet valve 1521 b provided in the secondhydraulic circuit 1520 are maintained in the open state.

Because the abnormal operation mode and the inspection mode in theoperation method of the electronic brake system 2000 according to thesecond embodiment of the present disclosure are the same as those in theoperation method of the electronic brake system 1000 according to thefirst embodiment described above, a description thereof will be omitted.

1. An electronic brake system comprising: a reservoir in which apressurized medium is stored; an integrated master cylinder having amaster chamber and a simulation chamber and connected to a brake pedalto discharge the pressurized medium; a hydraulic pressure supply deviceprovided to generate a hydraulic pressure by operating a hydraulicpiston according to an electrical signal output in response to adisplacement of the brake pedal; a hydraulic control unit comprising afirst hydraulic circuit provided to control the hydraulic pressure to betransferred to two wheel cylinders, and a second hydraulic circuitprovided to control the hydraulic pressure to be transferred to theother two wheel cylinders; and an electronic control unit configured tocontrol valves based on hydraulic pressure information and displacementinformation of the brake pedal, wherein the hydraulic pressure supplydevice comprises: a first pressure chamber provided on one side of thehydraulic piston movably accommodated in a cylinder block to beconnected to one or more of the wheel cylinders; and a second pressurechamber provided on the other side of the hydraulic piston to beconnected to one or more of the wheel cylinders, and wherein thehydraulic control unit comprises: a first hydraulic flow path incommunication with the first pressure chamber; a second hydraulic flowpath branched from the first hydraulic flow path to be connected to thefirst hydraulic circuit; a third hydraulic flow path branched from thefirst hydraulic flow path to be connected to the second hydrauliccircuit; a fourth hydraulic flow path in communication with the secondpressure chamber; a fifth hydraulic flow path branched from the fourthhydraulic flow path to be connected to the first hydraulic circuit; asixth hydraulic flow path branched from the fourth hydraulic flow pathto be connected to the second hydraulic circuit; a seventh hydraulicflow path branched from the first hydraulic flow path; an eighthhydraulic flow path branched from the fourth hydraulic flow path; aninth hydraulic flow path in which the seventh hydraulic flow path andthe eighth hydraulic flow path join; a tenth hydraulic flow pathbranched from the ninth hydraulic flow path to be connected to the firsthydraulic circuit; and an eleventh hydraulic flow path branched from theninth hydraulic flow path to be connected to the second hydrauliccircuit.
 2. The electronic brake system according to claim 1, whereinthe hydraulic control unit comprises: a first valve provided in thesecond hydraulic flow path to control a flow of the pressurized medium;a second valve provided in the third hydraulic flow path to control theflow of the pressurized medium; a third valve provided in the fifthhydraulic flow path to control the flow of the pressurized medium; afourth valve provided in the sixth hydraulic flow path to control theflow of the pressurized medium; a fifth valve provided in the seventhhydraulic flow path to control the flow of the pressurized medium; asixth valve provided in the eighth hydraulic flow path to control theflow of the pressurized medium; a seventh valve provided in the tenthhydraulic flow path to control the flow of the pressurized medium; andan eighth valve provided in the eleventh hydraulic flow path to controlthe flow of the pressurized medium.
 3. The electronic brake systemaccording to claim 2, wherein the first valve is provided as a checkvalve for allowing only the flow of the pressurized medium from thefirst hydraulic flow path toward the first hydraulic circuit, the secondvalve is provided as a check valve for allowing only the flow of thepressurized medium from the first hydraulic flow path toward the secondhydraulic circuit, the third valve is provided as a check valve forallowing only the flow of the pressurized medium from the fourthhydraulic flow path toward the first hydraulic circuit, the fourth valveis provided as a check valve for allowing only the flow of thepressurized medium from the fourth hydraulic flow path toward the secondhydraulic circuit, the fifth valve and the sixth valve are provided assolenoid valves for controlling bidirectional flows of the pressurizedmedium, the seventh valve is provided as a check valve for allowing onlythe flow of the pressurized medium from the first hydraulic circuittoward the ninth hydraulic flow path, and the eighth valve is providedas a check valve for allowing only the flow of the pressurized mediumfrom the second hydraulic circuit toward the ninth hydraulic flow path.4. The electronic brake system according to claim 3, further comprisinga dump controller provided between the reservoir and the hydraulicpressure supply device to control the flow of the pressurized medium,wherein the dump controller comprises: a first dump flow path providedto connect the first pressure chamber and the reservoir; a first dumpcheck valve provided in the first dump flow path to allow only the flowof the pressurized medium from the reservoir toward the first pressurechamber; a first bypass flow path connected in parallel with respect tothe first dump check valve on the first dump flow path; and a first dumpvalve provided in the first bypass flow path to control bidirectionalflows of the pressurized medium.
 5. The electronic brake systemaccording to claim 4, wherein the dump controller further comprises: asecond dump flow path provided to connect the second pressure chamberand the reservoir; a second dump check valve provided in the second dumpflow path to allow only the flow of the pressurized medium from thereservoir toward the second pressure chamber; a second bypass flow pathconnected in parallel with respect to the second dump check valve on thesecond dump flow path; and a second dump valve provided in the secondbypass flow path to control bidirectional flows of the pressurizedmedium.
 6. The electronic brake system according to claim 1, wherein theintegrated master cylinder comprises: a master piston provided in themaster chamber to be displaceable by the brake pedal; a first simulationchamber; a first simulation piston provided in the first simulationchamber to be displaceable by a displacement of the master piston or ahydraulic pressure of the pressurized medium accommodated in the masterchamber; a second simulation chamber; a first simulation piston providedin the second simulation chamber to be displaceable by a displacement ofthe first simulation piston or a hydraulic pressure in the firstsimulation piston; and an elastic member provided between the firstsimulation piston and the second simulation piston.
 7. The electronicbrake system according to claim 6, wherein the integrated mastercylinder further comprises: a simulation flow path provided to connectthe first simulation chamber and the reservoir; and a simulator valveprovided in the simulation flow path to control the flow of thepressurized medium.
 8. The electronic brake system according to claim 7,further comprising: a first backup flow path provided to connect themaster chamber and the first hydraulic circuit; a second backup flowpath provided to connect the first simulation chamber and the secondhydraulic circuit; a first cut valve provided in the first backup flowpath to control the flow of the pressurized medium; at least one secondcut valve provided in the second backup flow path to control the flow ofthe pressurized medium; an auxiliary backup flow path provided toconnect the second simulation chamber and the second backup flow path;and an inspection valve provided in the auxiliary backup flow path tocontrol the flow of the pressurized medium.
 9. The electronic brakesystem according to claim 8, wherein the first hydraulic circuitcomprises: a first inlet valve and a second inlet valve provided tocontrol the flow of the pressurized medium to be supplied to a firstwheel cylinder and a second wheel cylinder, respectively; and a firstoutlet valve and a second outlet valve provided to control the flow ofthe pressurized medium to be discharged from the first wheel cylinderand the second wheel cylinder to the reservoir, respectively, the secondhydraulic circuit comprises a third inlet valve and a fourth inlet valveprovided to control the flow of the pressurized medium to be supplied toa third wheel cylinder and a fourth wheel cylinder, respectively, andthe second backup flow path is provided to connect at least one ofdownstream sides of the third and fourth inlet valves and the firstsimulation chamber.
 10. The electronic brake system according to claim6, further comprising: a reservoir flow path provided to communicate theintegrated master cylinder with the reservoir, wherein the reservoirflow path comprises: a first reservoir flow path provided to connect thereservoir and the master chamber; a second reservoir flow path providedto connect the reservoir and the first simulation chamber; and a thirdreservoir flow path provided to connect the reservoir and the secondsimulation chamber.
 11. The electronic brake system according to claim10, further comprising a reservoir valve provided in the secondreservoir flow path to allow only the flow of the pressurized mediumfrom the reservoir toward the first simulation chamber.
 12. Theelectronic brake system according to claim 6, wherein the integratedmaster cylinder further comprises: a piston spring provided toelastically support the master piston; a first simulator spring providedto elastically support the first simulation piston; and a secondsimulator spring provided to elastically support the second simulationpiston.
 13. An operation method of the electronic brake system accordingto claim 4, comprising a normal operation mode, wherein the normaloperation mode comprises: a first braking mode in which the hydraulicpressure is primarily provided by a forward movement of the hydraulicpiston as the hydraulic pressure of the pressurizing medium to betransferred from the hydraulic pressure supply device to the wheelcylinders gradually increases; and a second braking mode in which thehydraulic pressure is secondarily provided by a backward movement of thehydraulic piston after the first braking mode.
 14. The operation methodaccording to claim 13, wherein in the first braking mode, the fifthvalve and the sixth valve are opened and the first dump valve is closed,and the hydraulic pressure generated in the first pressure chamber bythe forward movement of the hydraulic piston is provided to the firsthydraulic circuit by sequentially passing through the first hydraulicflow path and the second hydraulic flow path, and provided to the secondhydraulic circuit by sequentially passing through the first hydraulicflow path and the third hydraulic flow path, and wherein at least a partof the hydraulic pressure generated in the first pressure chamber issupplied to the second pressure chamber by sequentially passing throughthe first hydraulic flow path, the seventh hydraulic flow path, theeighth hydraulic flow path, and the fourth hydraulic flow path.
 15. Theoperation method according to claim 14, wherein in the second brakingmode, the fifth valve is closed, and the hydraulic pressure generated inthe first pressure chamber by a backward movement of the hydraulicpiston after the first braking mode is provided to the first hydrauliccircuit by sequentially passing through the fourth hydraulic flow pathand the fifth hydraulic flow path, and provided to the second hydrauliccircuit by sequentially passing through the fourth hydraulic flow pathand the sixth hydraulic flow path.
 16. An operation method of theelectronic brake system according to claim 5, comprising a normaloperation mode, wherein the normal operation mode comprises: a firstbraking mode in which the hydraulic pressure is primarily provided by aforward movement of the hydraulic piston as the hydraulic pressure ofthe pressurizing medium to be transferred from the hydraulic pressuresupply device to the wheel cylinders gradually increases; a secondbraking mode in which the hydraulic pressure is secondarily provided bya backward movement of the hydraulic piston after the first brakingmode; and a third braking mode in which the hydraulic pressure isthirdly provided by the forward movement of the hydraulic piston afterthe second braking mode.
 17. The operation method according to claim 16,wherein in the first braking mode, the sixth valve and the first dumpvalve are closed, and the hydraulic pressure generated in the firstpressure chamber by the forward movement of the hydraulic piston isprovided to the first hydraulic circuit by sequentially passing throughthe first hydraulic flow path and the second hydraulic flow path, andprovided to the second hydraulic circuit by sequentially passing throughthe first hydraulic flow path and the third hydraulic flow path.
 18. Theoperation method according to claim 17, wherein in the second brakingmode, the fifth valve and the second dump valve are closed, and thehydraulic pressure generated in the first pressure chamber by a backwardmovement of the hydraulic piston after the first braking mode isprovided to the first hydraulic circuit by sequentially passing throughthe fourth hydraulic flow path and the fifth hydraulic flow path, andprovided to the second hydraulic circuit by sequentially passing throughthe fourth hydraulic flow path and the sixth hydraulic flow path. 19.The operation method according to claim 18, wherein in the third brakingmode, the fifth valve and the sixth valve are opened and the first dumpvalve and the second dump valve are closed, and a part of the hydraulicpressure generated in the first hydraulic circuit by the forwardmovement of the hydraulic piston is provided to the first hydrauliccircuit by sequentially passing through the first hydraulic flow pathand the second hydraulic flow path, and provided to the second hydrauliccircuit by sequentially passing through the first hydraulic flow pathand the third hydraulic flow path, and wherein the remaining part of thehydraulic pressure generated in the first pressure chamber is suppliedto the second pressure chamber by sequentially passing through the firsthydraulic flow path, the seventh hydraulic flow path, the eighthhydraulic flow path, and the fourth hydraulic flow path.